Now I see why we have 8 mixes at hand...

The vqs-01 seems to works fine. We used it one a TV show a few weeks ago - not directly connected to the Catalyst but the signal going via SDI to the OB unit and back via SDI to the vqs-01 and the four projectors (they wanted to have live camera feed on the projection as well - so the Catalyst output was keyed in from the OB)

At that time I thought the vqs-01 was a good alternative to the TH2G - though it might be a bit more expensive.
Having a look at the available input resolution I am really missing the 4 x 1024x768 at 50Hz - that would be the one to have as XGA is still the standard resolution of most projectors - it might work with 25Hz when genlocked though.

When I get my hands on the vqs-01 next time I will try to do some testings...