Possible to make pitch/yaw control inputs relative to horizon rather than model?

Hard would it be to make the desired pitch/yaw inputs be relative to the horizon rather than the model itself?

I think it’d be neat to fly something like this: Flying Sidewinder missile - RC Groups where the model itself doesn’t really care which direction is “up”, kick it into a continuous roll, and then steer it around with pitch/yaw controls with the flight controller mapping the control inputs into whichever combination of control surfaces would yield the desired direction for the aircraft. I’m envisioning that the aileron stick would still be used to control the direction and rate of the roll.

This could also be used for standard-configuration aircraft to “cheat” while doing a rolling circle. It could be added to the “tricks on a switch” capability.

It seems like the sort of thing that a flight controller would be ideally suited for…