WARNING: DO NOT READ THIS IF YOU DON'T KNOW MUCH ABOUT D&D, and thus, are NOT a huge nerd.
I looked over the D&D item submissions. I'm a fan of D&D version 3.5, and a HUGE fan of d20 Modern, which is BASICALLY the same system. The difference between Modern and classic D&D allows us to extrapolate data on a type of armor found in a FUTURE setting, such as the Doom world. There is also Future armor, and I include this in the mix, but it sporadically follows the pattern of the first two systems, and only the heavy armor is really representative of the doom universe. All references can be found in
D&D 3.5:
http://www.wizards.com/default.asp?x=d20/article/srd35D20 Modern and D20 Future:
http://www.wizards.com/default.asp?x=d20/article/msrdthese are open to the public and free to distribute.
Making Green Armor for D&D 3.5 or D20 Modern:
For current items, I ASSUME that the items are modeled after 3.5. This means green armor gives average damage reduction 3.5 and +4 AC (NOT creating a miss chance of 20% with every hit.) The damage reduction makes the simplest armor pretty darn powerful, as if it were "Invulnerable," a +3 Enchancement. Not TOO unrealistic for a future armor, but I think there are more accurate items out there. If the item DID create a miss chance of +20% miss chance, it would be like the Ethearealness enchancement, which makes it WAY to freaking powerful, IMO. Plus, there are no weight stats, or max dexterity stats, etc. (I disreguard nonproficient stats, as those are only applicable to D20 Modern.) My armor suggestions give all of these. If the armor is NOT version 3.5, then we have no issues, as my suggestions give a new 3.5 armor.
There are three types of armor in Doom (G, B, R.). There are ALSO three CATEGORIES of armor in D&D and D20 Modern--light armor, medium armor, and heavy armor. It makes sense that green armor is therefore light armor, blue is medium, and red is heavy. You could argue differently, but we only have one style of player, the unnamed marine, and if he is a bruiser-- a fighter (3.5), soldier (d20 Mod) type character, then this assumption is valid. (whereas if he was some super dextrous character, he would do better in green armor then in red, and my whole argument would be thrown in the toilet. And don't start saying different level up patterns represent different characters, we'll be here all day. Just say that the different trait/level ups are "feats" and we'll leave it at that.)
Lets take a look at the SECOND best light armor in Iron Age/D&D 3.5 terms:
Studded leather +3 AC +5 Max Dex –1 Armor Penalty 15% Spell Failure 30 ft. Max Move 20 lb. Weight
BEST light armor, 3.5:
Chain shirt +4 AC +4 Max Dex –2 A.P. 20% Spell Failure 30 ft. Max Move 25 lb. Weight
Now look at the BEST light armor in Modern Age/D20 Modern terms:
Undercover Vest +3 AC +5 Max Dex –2 Armor Penalty 30 ft Max Move 3 lb. Weight
There is no comparable D20 Future armor; therefore, we'll create the Doom armor now.
Basically, the idea is that futuristic light armor gives about the same defense as modern or archaic armors, but is far lighter and easier to wear.First and foremost, the best d20 Mod light armor resembles the armor second only to chain shirt. However, our doom armor will look like chain shirt because it's easy to identify the pattern of improving armors if you look at a table of them. AC and Dex are the same for modern and 3.5, so we can easily extrapolate a basic idea for doom armor based on chain shirt: +5 AC, +4 Max Dex. The bump up in AC represents the improved material of future armor. Armor Penalties are nearly the same--d20 Modern has some harsher penalties than future or 3.5, and we will ignore these. We assume that our doom armor has -1 A.P., as this the next step up from chain shirts, but not 0, because surely there is an even LIGHTER doom armor just not mentioned. Spell failure is VERY NOTABLE-- as far as I can tell by searching the SRD and the wizards of the coast official rules modifications, modern armors
have no spell failure chance! We can extend this pattern to future armors, meaning items that create spells, such as the soul cube in Doom 3, never fail. This makes sense, because it doesn't. Speed always stays the same, and does so with our armor. Weight is the OTHER exception-- there is a MASSIVE difference between modern and archaic weights. Future armor doesn't really get much lighter (d20 future armor is just a tad bit lighter than d20 modern armor.) 3.5 light armor is about 6 or 7 times as heavy as modern armor, so our doom armor WOULD be 1/6th the weight of chain shirt, 4 lbs, but like i said, future is lighter than modern, so we'll make it 3 lbs, just like the undercover vest. Note that no one value is particularly high; the armor is just better in many ways than it's predecessors. As for damage reduction, that depends on whether or not you want to include those spell failures, or whether or not you even have spells in your campaign. Discussed below.
As a side note, d20 modern has it's own stats for leather armor and chain shirts, but these are non-canon and we're basically making D&D items anyway, so we'll totally ignore these P.O.S. items.
The End Result:
Green Armor: +5 AC___+4 Max Dex___-1 AP___0% Spell Failure___30 ft Max Move___3 lbs Weight___
DR +1/+0Final Analysis: As far as D&D is concerned, green armor would be the BEST damn armor available for light armor wearers, period. Primarily because it has no spell failure, and that makes it a spellcaster's wet dream. (remember, it is NOT enchanted or special in any way, unlike the rare armors listed in the DMG.) But in addition to the spell failiure, the +1 to AC and lower armor penalty give it properties similar to a +1 magic item, and the 3 lb weight limit is essentially like another +1 enchancment. All in all, if you actually used this armor in your game, it would be like adding two or three levels to your spellcaster, or using armor that has a +4 or +5 enchancment. (+2 if you decide to use spell failures) If you decide to use spell failures, however, the +2 isn't so hot, and thus, I think that a DR +1/+0 is both doomish and necessary. Keep in mind, this is WITHOUT magically adding other spells to the armor, which would make it even MORE badass.
As far as D20 Modern is concerned, the armor is still pretty good, but not incredible. The +1 AC and lower AP give it a +2 enchancement, increasing the value of a similar armor by about 40%. Keep in mind you could still mastercraft this armor, making it even better. There is a similar MEDIUM armor in the game, below:
Medium Armor
Concealable vest +4 AC +4 Max Dex –3 AP 25 Max Move 4 lb. Weight
As you can see, it lowers movement, and it's stats are worse, AND it's medium armor, so you'd have to take
another feat to get it. All in all, if you put green armor in a D20 Modern game, it would be QUITE a nice item to have, especially for someone who isn't too good at wearing armor. Not as good as in 3.5, but not bad nonetheless. I wouldn't put DR in it in this genre.
Conclusion: There you have it. I stress to you that this is not a strictly DOOMISH armor, but merely the future setting armor that would be created if we follow the patterns given in D&D and D20 Modern. You MAY not think that armor that weighs only 3 lbs is realistic, or that it's too weak, or whatever. I stress that, with the exception of DR, I am ONLY following the trends given by WOTC. I will await your comments before I place this in the wiki, and will proceed to analyze blue (medium) and red (heavy) armor.
EDIT:
I decided that the lack of Spell Resistances in d20 Modern is a typo--there are a SHIT LOAD of typos in the d20 Mod book (don't buy it, it's a waste of money, you'll have to spend 2 hours fixing all the screwed up rules, just use the SRD) Therefore, in my final wiki format, I will add a SR.