DjiMark... I am no expert on this.. but years ago someone posted about a setup they called WOBBLE STICKING.. They would mount a stick across the tops of both sticks. I believe they used ball joints to make it very secure and with no slop at the connections. The advantage for a one handed flier was you could sort of twist the cross piece to control elevator, and throttle together... yet (kind of) seperately.. while leaning both sticks left or right would make both ground handling, and rudder aileron mixing possible.
It obviously also makes some bad control mixing in some situations.. like crosswind take offs and landings, and trying to do precise rolls and flat turns.. However. If a person was wanting to fly badly, and maybe more scale type flying than 3D type flying.. Its an option. I must admit there is a certain thrill to the idea of learning this technique.. as it would be very challenging to learn/relearn?
Have fun with whatever you choose to do !