Needless to say, the Wii would have no trouble running a PSOne emulator. Nor would the GameCube, for that matter. (Remember, Bleem! ran on Dreamcast.)
I have a feeling that a lot of PSOne games are not filling CDs because they have a that much content but because they have CDs to fill and have no reason to care about compression. If they did a quick modification to the games so that they could use H.264 and Ogg Vorbis (or some other modern codecs) for the FMVs and background music, then they would be no larger than an N64 game. (In their defense, the PSOne was not probably powerful enough to decode those codecs, at least not during gameplay.)
If Square-Enix were to not release Chrono Trigger (hopefully the PSOne version/a Wii VC port of it) on Wii, then they would be idiots. Chrono Trigger, along with all the other SNES classics that people have been listing in this thread, would essientially be free money for Square.
On Star Ocean/SD3... well, they were translated, just not by Square. It would be quite amusing if Square were to buy the fan translations of those games. Square would probably want to still run some QA, but the work is pretty much already done for them. Or also the bug fixes for other games. (Ex. Someone added 2-player support to Secret of Evermore.)