I really don't understand what the "problem" with 72 MHz is.  Use PCM with fail-safe and get a switchable frequency module so you don't have to wait for a pin.  The only reason I see to go to 2.4GHz is that so many cheap models are available.

Actually, so many of you have gone to 2.4GHz that I am just fine on channel 47.

Thanks,
Bob Burrill