I think he meant take the internals of a ps2 and put them in the old school ps1. I don't think anyones done that. It would be even cooler if you could fit a new mini ps2 into a mini ps1, and spray paint it black or something.
Haha, there used to be a commercial model that was a black PS1 that was said to have better graphics and crap but it was expensive and it was out just before the PS2 so it didn't do well.
That was called a 'Net Yaroze' and was a playstation you could program with, basically you made games in C++ and tested them on the N.Y. It cost about £500 when it came out, the price really didn't come down untill PS2's were coming. If you had any old Official Playstation Magazine CD's [uk] they sometimes had crappy little games on them, they are the kind of games that were made with the N.Y.
Would be funny yeah lol, but nonetheless, totaly useless, unless you found a way to overclock the ps2, and even then, i'd bet its still a waste.