Thanks for the replies all...

FWIW I just ordered a 26" x 2.0" Schwalbe Marathon Plus Tour to see how it does...

http://www.schwalbetires.com/bike_ti...thon_plus_tour

Point taken though... might be ANY tire has its limits.

I'm still leaning towards dual-purpose-type treads for the short stretches I'm off of paved surfaces.

My concern was that, on a tour, with more hours spent on the bike my flats would multiply accordingly.

Might be though that I'm riding through exceptionally rough conditions.

Mike