but I haven't seen any receiver for them that could be plugged
into an aircraft radio microphone input.

Eric,

On paper the Jabra A210 looks close to what you would need to pair with
a standard bluetooth headset:
http://www.jabra.com/JabraCMS/NA/EN/...A210/JabraA210

You'd probably need to make a 2.5mm socket to Aviation radio jack
adapter lead to connect it to a radio.

The suggested temp range -10degC to 45degC and yet another 2 Li-Ion
batteries (headset & receiver) might conspire to make a cool solution
possibly more trouble than its worth?

Cheers
Neil
Christchurch, NZ