Most of the 3 and 4 channel Spektrums have a 3 position capable aux channel. I know the DX3.0 and DX3R do anyway. DX4C would be an option, 20 models, has the 3P capability, around $100.
I suspect Airtronics and Futaba offers it too, I'll take a look, If can find anything will advise.
Last edited by Dave H; 05-16-2015 at 10:43 PM.
Reason: DR3R typo