Merry Chrismas Dave,
It sounds to me like you may have a disk array issue, like its not fast enough to caputre the Uncompressed HD.
Perhaps try a Blackmagic 1080 easy set up to Jpeg or DVC pro HD and see if the disks will keep up.
On the camera control and timecode thing, you may get lucky and be able to capture your video via the Decklink card, but control the camera via Firewire.
Worth a try, hope this helps?
All the best, Peter.
Peter Barber
Blackmagic Design