Rpg Maker uses charsets such as the one attached below
In this pack there are two versions of everything, a 6 frames version - which is more flexible, but not compatible with RMK unless you are using some custom scrupt - and a 3 frames version (3f), alloted exactly how RMK would expect a charset to be.
So just grab the 3f version of any body/skin, slap some 3f clothes, 3f hair, 3f whatever over it and you are ready to use it on RPGMaker.