In theory it should be easier to mod then an MMO, but I don't see any info regarding the game engine used on the wiki....and the fact it was an Xbox exclusive, and then I am assuming ported to PC also makes me wonder.
XeNTaX • View topic - Sunset Overdrive TOC and files
This is one of the few post I have found regarding cracking the game (with no response), also an example of the file structure posted at that link.
Its a long shot but you could try texmod, Umod, or Resorep.
Edit Update:
Sunset Overdrive Nude mod potential.
If that is legit then hex editing to invalidate the mesh might work.