The P2 card already exists with other Panasonic cameras and is supported with v.5.1 of Xpress Pro and Adrenaline 2.1 as I mentioned. It is being used in news and in quick turnaround type programming.
Support for the HVX200 camera cannot happen until the camera ships, but the technology is only a transport medium and has nothing to do with the camera or the format that sits on the disc.
As far as success of DVCPRO capture over FireWire, I can only say that the supported laptops when tested in house can capture directly from FireWire. Playback and editing performance may vary depending on speed of drive, the number of video tracks etc, but this is different that a single capture stream.
Michael