I can find video transmitters from 5.8GHz down to 433MHz with the latter being ideal for longer range, but I don't see nearly as much diversity as far as control transmitters. Am i correct in saying that a lower frequency transmitter will almost always go much further than that of a higher frequency, with transmit power being secondary in affecting range? The extension of this would be that the control link would be lost far before the video if the video is TX'd on 433MHz and control on 2.4GHz. I assume that this would be dangerous since, for example, if video is gradually lost, you have a chance to return the craft to a location if better signal, but you don't have obvious warning signs for control being lost.
Edit - I know that there are 72MHz control transmitters, but i don't know of any way to use them on a quadcopter.