Thanks. At this point I am leaning toward bikes that can handle both 700c and 650b. That way I can have narrow "paved" tires and wider "unpaved" tires depending on the tour. While I would guess most frames could theoretically handle both wheel sets sizes, it is the 650 width that seems to be the limiting factor. The total outside wheel diameter going from a 700x35 to a 650x55 should be about the same so the bike's handling should not change all that much.

Tailwinds, John