Pat
I added an Airlift 1000 kit
http://www.airliftcompany.com/al1000.html to our Odyssey as per recommendations over at the Odyclub forum.
Although with the WDH I was able to level the TM and van, I wanted to supplement the WDH and stiffen the rear end to help eliminate the rear end bounce. I chose this kit over airshocks based on bad experiences with air shocks years ago (they leaked) and also the guidance over at odyclub. Installation was a solid 4 hours but fairly straightforward. I also replaced both rear shocks with KYB GR2 shocks since the rt rear was leaking.
What surprised me the most was that, with the van empty, the airlift kit only raised the rear end ~1/8" going from 0 psi to 30psi. It is not a "lift kit" in the sense of a 4x4 lift kit but a rear end stiffener!
It works well. We have taken a couple trips since the install and have really noticed the smoother ride. Although you still know the TM is back there, it is much less noticeable. My easily carsick wife did fine without the usual dose of dramamine to keep her stomach calm.
Troy