Thanks for your kind words Jan.
The reason I made a dual channel system was that it allowed me to make fine adjustments of the idle speed. I find that on the Eurostar the idle speed is quite critical. If it is set too high you never land, you just float on down the runway!
Let me know how you get on sourcing the parts. Most of them I had lying around at home, the Lego I stole from my son ;)
I think that everything could be bought from eBay. The servos were given to me by a friend. They were specially made for a product where he works. I think that you could take a normal radio control servo and remove the control circuit (including the potentiometer) and just connect to the motor directly. I don't know whether they have and internal stops that would need to be dealt with.
Kevin