I was Greg's (29er's) partner on that 100 mile ride and our kit of 40lbs shared was extremely easy to tote. I had 3 pounds on the bars 4 pounds under my seat and maybe 4-5 pounds in the frame bag. That left roughly 10 pounds on my back depending on how much water we had at the time.
On the bike, we were able to ride like we normally do which means getting some air, carving swift turns and ripping singletrack like usual. Off the bike, we still had warm meals, 3" sleeping pads and slept in a mountaineering tent. I had more gear than needed. That kit could have easily allowed for up to 5 days of travel. If on non-techincal terrain, it would have been far quicker than a fully loaded bike.
Beyond five days, we would have probably had to add rear panniers. Beyond 10 days, maybe front panniers. By then, riding would be a slog, not my idea of fun. Been there.
I've done several long tours with fully loaded panniers and one with a BOB. You have to like touring for what it is to ride with a full load. I get bored with a full load. You can't go fast, you can't carve turns, you just sit and rotate the cranks. For that reason and that reason alone, I won't do the fully loaded touring thing again unless I'm crossing some extremely rugged and remote expanse of land.
As for good panniers and racks, I'll vote for Old Man Mountain Racks and Vaude panniers with my second choice going to Ortlieb or Pacific Outdoor Equipment. I saw their new panniers at Interbike last month and was very impressed.