Hey Otto,
you have touched some very good suggestions here. For the fan I see an opening that can be discussed wiht my friends flying indoor. They are using very light, self winded brushless motors (taken from an old cd-rom).
The front engine is causing no troubles I think, that couldn't be overcome. It is the rear part that needs more thought. I need to loose some wheigt over there. Anyway, I will start this the soonest next year, so I hope for more feedback from everybody; as I said before... good research is half the work!
thank you and see you at scalebuilder.