Before I became more concerned about weight, I always used a Thermarest Trekker Chair. (They once made a few versions, including one which wrapped all the way around the pad - and weighed more than the pad.)

The one they have now is a nice design - you can let the top and bottom of the pad extend out beyond the pad, essentially giving you the ability to never have to dis-assemble the chair/pad combo.

Personally, I believe the chairs work better with the Prolite/Prolite Plus or other self-inflating pads than they do with inflatable air mattresses like the XTherm or Uberlite pads. The self-inflators seem a bit stiffer, which helps with chair stability.

Kind of miss my old chair kit - but it's too heavy and not rigid enough for the trips I do now.