This "X harness" is an interesting idea, and sounds like a great solution for you guys with 9 channel tx's.
You should just use the 1222 rx with a 9303/9503 tx, and then use the extra rx ports for your power (not signal) to the extra servos. You'd have 2 extra ports for ailerons, and one extra port for rudder.
This could work real good, and if retailers were smart, they could even start selling these "X harnesses".
The 1222 rx is only about $60 more than a 922 rx.
Now here's a simple and inexpensive way for you to get good current flow without forking out the extra money for the high dollar 12X tx. (Although I think the 12X is worth every penny)
Jim