... been busy with my own website lately!
As far as production goes, I can only quote myself:
After that, [racing success] it's time to think about production - it won't be a good idea to release a car that still has some flaws in it, though it even happens with big companies.
So to speak, there are no plans yet - though you can be sure that if everything works out and there's enough interest, the guys behind team GEKKO would try their best to make the car available.
alloy bulkheads: DCM already explained it, besides, a TC3 (or any other GB) would not fit the GEKKOs layout (well perhaps the Academy SB-V2's that is not available yet)
broken B4 arms: the reason, why the arms on the BJ4 break quite easy is the fact that they're mounted "around" an inner alloy bulkhead. That means that an impact load will make the A-arm hit the alloy block with it's front mount.
The GEKKO uses two bulkhead braces that sandwich the arm - which can transfer impact loads with the front and rear mount (or more precise: can absorb some of the impact load with it's inner X-shape)
Additionally, Delrin Pivot balls are used in the rear brace that provide some dampening.
As far as I'm informed, only one A-arm was broken up to now - during a full speed crash into a pipe.