I've been wishing for a while now that there was a place that had archived the different Photosynth viewers where I could test out any given synth in any of the viewers, from the HDView-based CTP version from 2006 to the RTW Direct 3D viewer to the Silverlight prototypes with leaf nav, the Silverlight 2 viewer, and the Silverlight 3 viewers (both control scheme versions).
I know that the Tech Preview plugin and the RTW plugin didn't necessarily like being installed on the same machine, but I would absolutely love to play with some of my current synths with the photo tray, splatter mode, camera frusta, etc. intact. I also realise that the not all of the controls of the CTP plugin would work with newer synths (the little aerial tour comes to mind).
I know that this is getting away from you guys making progress on new features but I would absolutely love being able to switch between different versions to compare controls and performance.