I really like the idea of it clamping on my seatpost instead of the frame, and those others are a minefield trying to get them on. Hey, I remember another on the Rivendell site! Look at this. The silver hupe.

I may have to give this a shot. Like I said, those Bagmans are heavy, but I guess if you get the titanium one it won't be. They are so hard to find!