I'd suggest checking up on Mortal Online, it's Full loot, First person combat real time, and sandbox. I.e userdriven economy and all that it brings, it's up to you to decide what you'd consider a quest and whom to hire for how much..
If they're not pleased with your offering they might decapitate you.
It's not out yet, but it has a steady marketing plan and i know some of the people working on it and i must say i'm pretty sure it'll be out by summer 09'
www.mortalonline.com
Teaser Trailer:
http://www.youtube.com/watch?v=yqko1Xuv8wQps. Epic encounters and 'bosses' will be devs controlling, and the monsters are unique and won't respawn. Have you ever played Ultima online?