Hmm. PC RPGs with a cute appearance? Is she looking for single player or multiplayer?
If SP, then you could always try tracking down an ancient copy of Final Fantasy VII: Ultima Edition. Not my favorite game in the world, but a good one nevertheless.
Continuing on with the SP cuteness in RPG format, does she get much into dungeon crawlers, ala Diablo? If so, then both "Fate" and "Torchlight" have a very cute aesthetic to their graphical presentation that she might enjoy.
And on top of all this, I do believe Steam is now carrying the Phantasy Star titles, innit? If she can go old-school, those might fit the bill for her too.
For multi-player, you've got plenty of MMOs to choose from. Ragnarok Online used to be big -- is it still big? It had very cute graphics, and seemingly deep character customization to boot, so that might be an option. Or, for something free, try Fiesta. There's also a Cartoon Network MMO out there that I've played a bit, it's not too great but it's got a few nice features.
Also, anytime someone's looking for an RPG of any kind, I have to recommend Kingdom of Loathing. Seriously, greatest internet game EVAR.