Vista has a pretty good remote/fail over system. I would suggest to try that. It pretty much pops up if you are on the same network with a machine running the same vista software.
In my case i use an extra macbook but i also tried it with a windows surface tablet on 5Ghz wifi. In many theaters there are ethernet connections like you discribe. I put my main machine on the FOH and connect it with a second machine on stage for focusing. You could then connect the mv to that machine and even see what you are doing.
(I would’nt suggest the wifi option for shows but it’s great for focussing and patching!)
In general there are(/where) a lot of problems with usb over ethernet and there is only limmited hardware really working with it. I can’t explain but my guess would be the signal and timings from the MV would probably be to complex to be recognized well on the other side. (I haven’t worked a long time with usb over utp, maybe time has changed but the fact that there isn’t very much good info and hardware available makes me think it isn’t a lot better nowdays). And again in my opinion, nowdays its easier to find an extra machine then to buy some hardware what might not work.
Correct if i’m wrong.