I think that list of uniques (with the "times found" number, and, i guess, with description of that unique) should be stored in one list, while amount of kills with each weapon (unique weapons too) should be stored in another. It won't spoil anything because weapons should appear in "amount of kills list" only in the amount is more than 0. Also that would be good because uniques that are not weapons (so with which you cannot kill anyone) won't have a permanent 0 in "amount of kills with this item" - otherwise it would be a design failure. Uniques that were not found should appear in the list, but should have "not found yet" in all the values. Because it won't hurt anyone to know, how much of them are left to find. Imagine that you have a list of all uniques except, for example, the Railgun. But you don't know either you found everything, or if there are anything left. While, if you would know that there is one left - you would have bigger motivation to search for it.
How to represent table of "Amount of kills"? It seems to me that the best way is to place monsters in the columns and weapons in the rows. Like that:
Weapon\Monster Former human Former Sergeant
-------------------------------------------------------
Fists 236 12
Combat Knife 428 4
Chainsaw 982 1
Butcher Cleaver 152 1
Pistol 578 14
Gramatton Beretta 73 0
Trigun 49 0
Anti-Freak Jackal 54 0
Shotgun 693 43
Combat Shotgun 973 27
Double Shotgun 435 15
Assault Shotgun 26 0
Pancor Jackhammer 73 0
To see monsters that are to the right - make "right arrow" key to scroll one monster at a time to the right (not one line of characters at a time) and make weapon names always visible to the left (fixed, so only amount of kills and monster names would scroll when scrolling right). Same for vertical scrolling. To avoid low amount of kills per view - i have one idea. Abbreviate long names into several letters that are distinguishable from each other and make some moving cursor in the shape of the cross (so it would highlight current row and current column). And that current row and current column would be larger that the ones that are not highlighted (large enough to show full name of monster at the top and the full weapon name to the left). Like that:
Wea\Mon FH Former Sergeant FCp
-------------------------------------------------------------------------------------
Fis 236 12 456
CKn 428 4 645
Chsw 982 1 6
ButCle 152 1 6
Pstl 578 14 456
GrmtBer 73 0 45
Trig 49 0 456
Ant-F J 54 0 65
Shtg 693 43 48
C Shtg 973 27 347
D Shtg 435 15 15
Assault Shotgun 26 0 0
PanJck 73 0 0
Well, now i see that with monster names such thing works, while with weapons that produces only a waste of space. Well, we could output full weapon names, but at least make current monster highlightable.