Hello Tim,
I can create a 3D world, just like a game. People can walk around as an avatar which can be created from selecting various options like male/female, hairstyle, and various clothing options. These people can also chat and collaborate with one another within the 3D world which can be designed to look like anything you want.
The cost for this project depends on how many avatar options you require, the level of detail required for the 3D world and server load based on how many people will use the 3D world at any one time.
Any questions, please ask.
Many Thanks,
Gavin.