Well that depends. A PSOne( PSX MIni ) will not yeild a high price but a modded PSOne or PSX will yeild a high price.
So mod that PSOne or whatever. Also a PSOne with diffrent apearances or looks will gain value but it depends on how much a person knows about the technology.
Also there is going to be PS3 and you can play most PSX games on Pocket PC and even cellular phones. You could probably run psx games on your gba with a kart that has a 3d chip installed.