Well...it's a good idea. But it could get unfair if it gets carried away.
Really, I would be fine with it even if it was only for looks, without any stats involved. Of course, then it shouldn't be really expensive.
But if it's handled right, and the armor and weapons are within limits (no getting random stuff, like orange construction helmets), it could work with stats. This would add a whole new demenision to the game, and would hopefully make it a lot more fun.
Of course, a lot has to get done before then...