If the state of CHKD is still what I think it is--finding the communications and control hooks for the USB controller in the camera is still the first stopping point...
At the risk of making another off-thread suggestion (assuming that USB comm is not happening soon)...
The only other high speed method, that I am aware of, which can access camera data while the camera is operating are the Wifi type SD Cards...
I don't have any experience with them, but for a $100, it might be worth experimenting with a
Eye-Fi » Home 2GB card...
Plug the USB mixer into a WiFi enabled laptop and a process monitor would allow you to download the USB sound and the Camera video (once the recording has been stopped) to the laptop for immediate "joining" (software work required to automate).
You would still need to sync the start of the video with the start of the USB audio recording... You could use the computer to control the USB remote to start/stop the camera (or use the auto-focus LED under uBasic control fed back to the laptop)--you would get withing ~10mseconds--or possibly down to the 10usec. syncing of data (look at the stereo camera threads--I think with their software/process they go to <10usec sync between the two cameras).
Another "exact" sync possibility would be to place a small transducer at both the camera and USB mic's and emit a click a few 10's of mseconds into the recording and look for that when aligning.
Another method would be to simply log the video start time (from file and/or sync pulse from camera to USB recording computer) with the USB audio file (tag or log file)--again using the Eye-Fi card to access the camera data in near real time.
-Bill
