I'm not sure on the Hauppauge ? HD PVR. MC supports most Hauppauge devices.
Yes. The HD-PVR is supported, though it takes a bit more setup than it does via Sage. You have to have installed the WinTV software that came with the HD-PVR, not just the drivers, for it to work. It uses a filter or splitter or something included as part of the WinTV install. Sage includes its own version of this filter, so I'd never even installed WinTV, much less actually tried using that POS.
The Collosus not yet, but it'll be coming along before too long I suspect.
Jim... Very interesting to hear that you're hopeful about CableCard. I'd buy one of those fancy 4-"tuner" CableCard devices immediately if MC supported it.