Ken,
I am in the same boat, I have about 10 FrSky Hitec compatible Rx's and 3 Hitec Optima 6 Rx's.
I had been using a Hitec external RF module in my Futaba radio and about 3 years ago I purchased a JR-style Hitec module when I started looking at FsSky radios. In case the JR-style module fails, I can use an adapter made by Flytron in England to use the Futaba style module in the JR-style mount in the back of the FrSky radios. So if you have a Futaba style external module for Hitec, you can use the adapter on FrSky X7 and others. The smaller FrSky radios like the X9 Lite and X-lite use a mini-module. Aloft sells a Multi-protocol RF mini-module, but it does not support Hitec. Blame that on Hitec since they are quitting the Radio business.
It really would be nice if FrSky came up with a conversion firmware update to flash into the FrSky Hitec compatible receivers to make them compatible with the FrSky V8 series. That would solve a lot of headaches for those abandoned by Hitec.