I'm sticking with R-12 because I have a good supply of gas, but I've been doing some research on the Barrier Hose issue and the conversion process. As you may recall, the estimate to change over at Prevost was 40 - 50 hours in labor because of the hoses.

This is one paragraph about hoses from a very good Tech Article:

When R134a was first introduced, it was thought that all non-barrier/ nitril hoses would have to be replaced during a retrofit, but later testing has shown that the mineral oil used in an R-12 system forms a natural seal. In most cases, the R-12 hoses will perform well, provided they are in good condition. This is also true for O-rings, unless the fittings have been disturbed during the repair or retrofit, replacing O-rings should not be necessary.

The entire Article is here: http://www.shoptrac.com/r12retro.htm

I realize this is a "who gives a rat's ass" for later coach owners, but I would guess there is a bunch of R-12 guys out there and I question the mother ship (Prevost) on the need to spend north of $7,000.00 for a simple conversion.