Take a look at the URL and see what you think of the idea for a round tube split block jack point for the main gear. This tool would be handy for removing a wheel / tire or wheel bearing work. It is only a jack point and does require a floor or other style jack. This one is the Homebuilders "model" and it could be CNC router cut and still I believe, affordable.
Some of the issues are that MOST RVs have a different axle bend angle and as result the block would be unique to the Model. I think 6 s and 7 ( not A) have the same angle. the 9 as shown has a 48 deg angle and the 9A is ?? different. Don't know about 4 8 or 10s