What an odd camera...
http://www.dpreview.com/news/0911/09111001ricohgxr.asp
I like the idea of being able to swap the sensor. You could have different types of sensors optimized for different tasks. Much like in the film days. But why make the sensor and lens one unit? Okay sure, it makes it less likely for dust to get on the sensor. But it seems like this minor convenience would make the photographer's kit several times more costly... especially since your lenses, which on a traditional interchangeable system can easily outlast every other component, essentially become obsolete as new sensor technologies are introduced.