Mine are supplied built & tested Mark but I'm not a business, just a bloke in a shed doing it for interests sake.
Have a look at the Macgregor Digimac 1+1 emulation encoder, it does propo rudder and sequential throttle which you could use for D/T or whatever. Would that be ok?
Heres the demo:
https://www.youtube.com/watch?v=fHaUvmsJdU4
Theres also a 2+1 version but the 1+1 is more popular over here. Maybe have a read of the documents for each, they're on the Archive page of
http://www.singlechannel.co.uk
Alternatively if you're up for a challenge there are lots of controller boards now to have a go yourself - arduino, STM etc - all the 2.4g modules need is a conventional PPM stream.
Cheers
Phil