RE: Tethered blimp with fixed position camera
Well, if, for the moment, you take the blimp out of the equation. ... what do you have? A remotely-operated camera.
I know that my Sony has its own remote-control handset, so it could be controlled wirelessly at a distance. You'd have to strip out the excess weight, mind. A video TX/RX is cheap enough and easy to obtain.
Now, if you can just afford to buy the helium and the massive blimp ...!
What is the lifting capacity of helium, anyway?
Hot air is, I think, about 7 grammes per cubic foot.
That wasn't much help, was it?