the FMA and Hitec RX's that I have (FMA Extreme 4 and 5, and Hitec 555) are both duel converstion.

I'm sure you are right about the different intermediate frequencies in the futaba though.

The FMA website's FAQ is actually an intersting read. They do some intersting things with their RXs. I don't know exactly how, but they are a lot less sensitive to antenna length for example, and you can chop an FMA antenna almost in half and still have plenty of range. I've even tested this (not intentionally, my antenna was dynamically shorted by a passing propeller).

Also, I'm not sure, it's been a long time, but I think my old JR AM single conversion Rx's from way back were high/low band as well. I wouldn't swear to it, and I don't feel like digging around to find them to check

I agree, shame on the hobby shop.