WOW! Just found this engine. It's amazing from what i've seen in the demo.
If this game was based around 'there.com' by makena, this would make a fortune.
In 'there', you rent plots of land and can build in it. You can also submit your own designs like houses, buggies etc using 3ds max or Blender. You also have paintball. In-game speech would be nice too! 'There' has proper collision and vehicle physics too. I will def. be keeping an eye on this! I was a bit disappointed with the controls, but, being it's a demo, i'll let it pass. The vehicle driving left a lot to be desired.
P.S. this makes Second Life look silly and stupid. I hate the sector breaks in it!
P.P.S. could you make it so you have an option to lock the camera behind you.