lfs and its skin viewer, its 3d modelz skinnin method, give u more freedom, than the gamez u were talkin about. i mean in those gamez you can't make really unique textures.
I know those prgz, wid a programmerz point of view, and i can say they aren't so precise like lfs' method.
As the guys said u can use many public skins from many sites, and its very easy to modify the number and the racerz name on em. i think if u know the microsoft paint, i cant b a problem.