Thanks The Professor that did help. I guess as cool as they would be I probably can find something more mainstream to fill the gap (and save the money).
A lot of this will depend upon your budget and required pack size, but. . .
If you want another extremely durable set of packs, take a look at Kifaru or Lowe-Alpine. The Kifaru's are a little less expensive, but have proven very durable, so far. I use the Kifaru Navigator as the basis for my home kits. It's a little smaller, about 4000 cubic inches as opposed to the 6500 ci of the Mystery Ranch 6500, but external pockets are easily attached/detached (which is why I use it for the home kit - modularity). It's almost as comfortable over the long-haul as the Mystery Ranch and Kifaru backs up their packs 100%.
The Lowe-Alpine packs are very durable commercial packs, but Lowe has a VERY long tradition of packs being used in the military (I still have one of the original, special-run Lowe Vector packs with built-in rapelling harness). They have packs that run the full gamut of size ranges.
The down side of the commercial Lowe packs is that it's a little more difficult to attach external pouches, but this is easily fixed with some basic hardware such as fastex buckles and some ingenuity.
Hope it helps.