Thanks for the information, I am much encouraged by your plans.
I have not used Qt or wxWidgets (I am a retired s/w engineer) but the little I do know would cause me to lean towards wxWidgets. I believe that Qt is not fully open source which could give problems on the free version (I think this is the reason QCad community edition is not availble on windows), though I may have my facts wrong here.
I like the idea of allowing LUA scripting for extensions.
If you do this mostly for the fun and satisfaction rather than the money, have you thought of going open source? There is nothing available open source anything like as good as Cycas, if you got a few more developers onboard you could push the development forward much more rapidly. I would be interested in contributing myself.