Well we've finally done it! We now have a way for you to create or import your own models and put them into Virtual Earth using truSpace which comes from Caligari who we brought into Microsoft not too long ago. Not only that but you can get truSpace for FREE. You can also import models you have already from many of the popular 3D modeling tools into truSpace and then upload them right into Virtual Earth. So get it for FREE today.
Chris Pendleton has all the details. This is a long post but includes step-by-step instructions on how to load your 3D models into Virtual Earth so it's worth a read and also includes a great video showing how you could use truSpace to create a virtual retail environment. --Enjoy!