Is the tailwheel conversion for the C150 applicable to the A150? While maintaining aerobatic category, I mean. I don't think it affects the aircraft's aerobatic certification but I've only flown a C150 tailwheel so don't really know.
If aerobatic certfication is unaffected then a Texas taildrager might be a reasonable option. There are even STCs to upgrade the engine to something a bit more powerful. Again, would want to confirm aero. ability isn't lost.