Well, I control a remote PTZ HD camera from 200 miles away via IP. Sony-based, controlled thru the joystick on our Ross carbonate switcher. Due to about a 3-second lag, the camera position presets are your friend. The very fine control is not really there, IMO.
Newtek is all about integrated solutions for a need like yours, and you get so much with the package I think you’d have to consider it.
The concern that I would have is about the type and level of signal compression and the codec used to send green screen HD video back to a remote site for further integration. I mean, the Cable news orgs and networks do it like that on a daily basis, but I’m sensing your budget might not be on the same level. You need green screen as absolutely clean as possible to do the best job. Adding noise or taking resolution hits on multiple encode/decodes thru the various signal chains makes me nervous. To the point where I’d look at how to do the keying *before* sending it back. But that’s just me, worrying.