You might be able to import all the objects and stuff. 'maybe' even the maps/textures. But the actual game/missions etc would be a whole nother matter.
THe actual source code for GTA VC isnt out i dont believe, but there are people who've come a long way with GTA:VC for pc, Multi Theft Auto, which can be found
HERE. Allow's multiplayer and 'kinda' missions and deathmatch. So if anyone were interested id give them an e-mail/msg with your idea