I was playing one game and through out I didn't get one custom weapon. Now each game is random so the simple solution was to die.
However, that did get me thinking about something for the future, custom modding your gun after each level (each time you level or the end of each level).
So each time you level you get your normal trait level up plus the ability to somewhat mod one of your guns. Mods could be what ever you feel like, quicker reload, more damage, or bigger cap. Basically things that can be found already, but instead you get to choice what direction you want to take your weapons in.
Just a thought. (Been having way too much fun with the game, so thanks)