I played Phantasy Star IV and I LOVED IT. But maybe I was just really in need of an old-school 16-bit rpg...
Anyways, have you considered...
Street Gangs (aka River City Ransom? It's a brawler/beat-em-up with RPG elements and SHOPPING)
The Legend of Mystical Ninja (A very challenging action/adventure game, but with VC auto-save between sessions, infinite continues, and someone playing co-op it's a challenge that can be beaten)
Harvest Moon (More Sim than RPG but I LOVE THIS SERIES. This was Animal Crossing before there was Animal Crossing)
Zombies (aka Zombies Ate My Neighbors, more an action game, but with co-op and a methodical, level-based pace that makes it more engaging than run-and-gun)
Ignition Factor (Again, less RPG, more 16-bit era Firefighter Sim. Rewards planning and learning levels to beat them completely)
Chew Man Fu (Not an RPG, but sue-me, this Ball-Rolling (as opposed to Crate-Pushing) puzzle game is GREAT!!!)