There's a fair few 3rd party modules out there now, Spektrum being the best supported one.
I use the Assan modules (in a Hitec CRX radio - absolutely flawless, though module needs to be removed to save settings!), but would consider something like this if starting over:
http://www.giantcod.co.uk/frsky-v8ft...-p-405313.html
The receivers are also just as cheap, and from the reviews, perfectly reliable.