RH is correct; you can't mix Kinect with 2D video. Just curious but why all the bother? It sounds like you're attempting to turn a fairly simple process into an unnecessarily complicated one.
Ideally, you should use the same camera type for all cameras when recording. That said, it is possible to mix different 2D video types, for example, PS3 Eye cameras and regular HD cameras. To do so, you will need to composite your video clips in a format that iPi can understand, synchronize and color match the videos, and output it as a new movie file. You can see an example of how this works by looking at 1k0's
behind-the-scenes video for Danse Kabyle.This is just my opinion but it's a lot of extra work for no real gain in quality, cost savings, or efficiency. To be clear, higher resolution doesn't necessarily improve tracking quality but it will probably increase calibration and tracking time. Higher resolution is really only useful if you're recording a larger capture space, which is possible with PS3 Eye but not so with Kinect, so in this situation it makes no sense to mix them.
FYI, framerate is more important than resolution--higher FPS means little to no motion blur which can affect tracking accuracy. The PS3 Eye can record iPi data at 60fps, which is very good for a entry level system like this. The Kinect system can only do 30fps but it's the convenience of the system makes it worth considering. You really need to choose one system--by keeping the devices in a configuration the same, you can be sure that the data will be synchronized with consistent image quality. Also, by keeping the cameras the same, iPi Recorder will do all the formatting for you automatically--no need for compositing, syncing, or color matching, just plug-and-play.
Hope his helps.
G.