Scott, there are two possible solutions without going to another four pages. One would be to have a longer page for the back cover and have it folded over, similar to some of the magazine advertising (or the way the map for the Tampa RV show was in its program). The other would be to have a business card or sticky and have this added to the inside of the back page so it doesn't get torn off easily.
Of course, having just one more page is no problem to the online brochure.
I think it is important to have prospective buyers see this forum and the support that the factory gives its owners and the help furnished by those owners who are more experienced than the rest of us. If a person grabs a brochure, s/he is already interested somewhat in the product. The forum should make this interest perk up even more.