If you are judging it by the likes of the NES, SNES, megadrive/genesis, GBA and DS scenes then you will leave disappointed, hell even the GB/GBC probably did better (see things like Link gets Laid) than what has happened for the PS1 thus far. However you can do quite well for the PS1 and several people have pulled apart formats (one of the graphics ones is the TIM format), the debugging emulators are not so bad (not quite FCEUX or no$gba grade but far better than a lot of other consoles) and what anti piracy there is has been sorted quite well too. In short there if you had come to us and said "I really like the Seibu SPI System arcade board, let us hack the games for it" then you would be facing an uphill struggle and I would have said "I hope you are already a programmer or hacker", for the PS1 though you have good hardware docs, good emulators, the filesystem and AP is not going to worry you, several of the file formats are already known and you can probably find several like minded individuals. Comparing consoles then "like the Wii if you ignored the hacking work done for the Nintendo first party/captive dev games".
Crash Bandicoot racing had a tiny bit but more were concerned more with ripping to inject into other games.
You might also want to look at some of the gameshark creation people, if "without the source" means something to you then what a lot of them manage to pull off within the limitations of the gameshark world should be even more impressive. Going back to crash bandicoot there was some fair analysis done here, though you might as well watch
Some of the people did some stuff in the fighting game world. However again if you are going to compare it to things like Smash Brothers (though I am not a great fan of a lot of the work done there) it is going to be pretty basic.
Final Fantasy saw some efforts, though most here looked more at the PC ports for obvious reasons. If you want crazy drama though have a look at some of the Final Fantasy 7 retranslation stuff, enough whine there to keep me amused for years.
I know you said no searches but
http://www.romhacking.net/?page=hac...gory=&perpage=20&title=&author=&hacksearch=Go is a reasonable jumping off point. Several of those might not be the greatest as far as gameplay changes go but programming wise there are several there that will see me spot them a beer should we ever meet up.
