If your serious about the HH Mtn, you may want to wait for the newest edition of P.O.E pads. I sent an email to P.O.E awhile back with some questions. Where is part of thier reply:
Hyper High Mtn (HYHM) - This is a hybrid open cell/closed cell foam pad. The pad is bulkier than the AO Mtn in that it doesn't fold in half but rolls up the full 20" width and is about 7 inches in diameter when rolled. It is however lighter than the AO Mtn and is more insulative. The HYHM uses a layer of Aspen Aerogel in the torso and foot area that raises the insulation value to more than double of the current AO Mtn. Aspen Aerogel is being used by NASA and now more and more footwear companies to better insulate their shoes and boots, ie ice climbing and even long distance running in hot environments. Information on Aspen Aerogel can be researched on their website:http://www.aerogel.com/
The Hyper High Mtn site is below:http://www.pacoutdoor.com/2007/index.cfm...;amp;familyID=1
I mentioned above the current AO Mtn. I mention this because in 2008 we will be shipping an updated version of the AO Mtn called the AO Aero Mtn. This pad will have strips of Aerogel inserted into additional drill holes in the torso. They will be in between the current drill holes. It might sound counter intuitive but more heat is lost through the remaining solid foam rather than the currently drilled tubes. We are knocking down that thermal exchange by putting Aerogel strips in that foam area. The AO Aero Mtn's are currently in production and should be available this fall, probably by Nov 1, but I don't have a firm date.
I keep looking but am yet to see the new AO Aero Mtn yet.
After getting the above email, I ordered a pair of Aspen Aerogel insoles for my climbing boots. Their insulating effect make me very excited about the sleeping pad!!