You might try http://www.digitalww.com
Just bought a used VMI70A (equivalent to SP-716 from what I've read) that has separate round VGA and USB connectors.
Thought I was getting all the cables, but haven't heard back from the seller.
Does anyone know a source for the cables, or at least have a pinout so I could make them? I can post pics if that would help.
Also, I didn't get any driver disk either - anyone have a link or can send me a ZIP file?