I posted this in another thread but it was somewhat OT and got lost in the traffic.
Anyway,
Have you considered any of the automatic tire inflation systems on the market?
Here's one: http://www.saferco.com/vigia.asp
I've seen them on some tour busses and heavy trucks. From this website, it looks like around $1200. They certainly are not very attractive but if they became common someone would find a way to run them throuh the hub. I think that's how the Humvees work.
Len
Trucks run them up here in order to increase the GCVW. I looked into it once but I can't remember all the details. It seems to me you had to use the auto inflation systems because the driver had to be able to change tire pressures depending on whether he was loaded or unloaded and depending on the rating of the highway he was travelling on. I can't imagine why you would want the ability to change inflation pressure on an RV. Or the headache of maintaining a mechanical system that appears to be an accident waiting to happen.