There was a letter in the most recent issue of Trailer Life and writer talked about using a produce called Transit Shield that he saw at a RV show in Quartzite. Their web site is transitshield.com. Sounds like what you are looking for. If you end up using it, I would be interested in what you think because we are planning a 2007 trip to Alaska.
Stacy & Sharon Wise
"A good traveler has no fixed plans and is not intent on arriving."
Lao Tzu (570-490BC)
2003 GMC 3500 Juiced D/A
2004 Hitchhiker Discover America 31 1/2 LKTG Luxury Suite
MOR/ryde IS Suspension System