Usually 6meter modules are special order, but they do exist. I had a Futaba 8UAP on 50.880, and used it for many years. Upgraded to 2.4 recently. My club didn't even have tags for 6 meter. You can usually find the 50MHz versions in the higher end (10/12 channel) radios, but special order for an 8 or 9 channel TX.

Hope that helps. Personally- after flying 50MHz for several years, and then switching to 2.4GHz, I've noticed no difference in functionality. No glitches, although I had several with the 50 MHz TX, but that might have been a result of the RX itself.