I thought about doing this in the early '70's - I was flying fast aerobatic R/C models and a friend had a Piper Vagabond which was based at the same strip as we flew models from. The speeds were broadly similar.
In the end I didn't because it just seemed too likely to end in a plastic bagful of bits of my model, which had taken many hours to design and build, and quite a bit of my hard-earned.
The Vagabond didn't have a radio (IIRC) so that wasn't a problem but I was concerned that the range of my R/C system (normally perfectly adequate - in sight was in range) might be adversely affected by the Tx being away from the ground.
It would be extremely difficult to keep the model in sight at all times from the inside of a high wing aircraft - and you need to see it to fly it. Eyes off for a few seconds would probably result in a crash.
From where we flew, there wouldn't have been much risk to anyone except ourselves (and not much of that) but that was in the deepest wilds of Dorset.
Why do it? Why do anything a bit difficult?