I'll be very interested to hear how you make out with that.
Just to add some perspective, when I went to Henderson's Line Up to have some suspension work done, one thing I noted was the somewhat harsh ride in the rear (my year Concourse didn't come with More-Ryde, just with the usual Ford springs). They said it's a common problem with E-350 and smaller E-450's --- they do a lot of work with ambulances, which are often on these chassis, and you can imagine how they don't like harsh bumps as they are trying to start IV's or whatever.
There is the More-Ryde, and then there are the Sulastic shackles. But apparently a new "thing" is parabolic rear springs. I guess the rear leaf packs tend to be harsh with either the smaller chassis (E-350) or a relatively lightly loaded E-450. The parabolic springs are supposed to help quite a bit, but I have not tried them. I found a combination of other things that made it pretty decent (and figured I can always do parabolic springs in future without "backtracking"). I have heard decent reports about the Sulastic shackles from someone with an E-350 van with duallies.
I have a buddy with a fully loaded ~28' RV on the E-450 chassis (~14,500# plus a tow car) and it doesn't have the same harsh ride. So maybe there is something to the theories.
Henderson's did mention that they had put (if I remember correctly) an air suspension on an E-350 Chinook that a customer of theirs was using for a toad (!) behind a large Class A.
Anyway, cool that you are going for it and I'm eager to hear how you like it. Will you be able to use it for leveling too, like a Foretravel? That would be a sweet bonus