I have wide, flat feet. I wear a 13.5 in asics running shoes, width 4E. I wear some asolo powermatics (wide) for my normal backpacking boots, but am doing some higher peaks in the himalayas this fall and need some mountaineering boots.....any ideas on a pair that will come close to fitting?

Since you're going to the Himalayas, I wouldn't be above getting the Millet Everest because you're going to some serious elevation not to mention a serious primitive part of the world. Also, Millet sizes up to a US 15. Remember the saying: It's easier to keep warm than to try and rewarm. If your feet get cold up there, it's going to be hard trying to rewarm them. Downside: $799!

13.5 US, and thank you for the recommendation! although $600! ugh, that's a pretty big chunk of change. funny how being in %5 makes the price of my shoes jump up %75.....

Is that UK 13.5 or US 13.5? If it's UK 13.5 then it's really is US 14.5. If you're US 13.5 then I would probably start with La Sportiva Baruntse because they run in Euro size 48, 49, and 50. The reason why I suggest this boot is because it's a serious non-plastic double-boot that's in your size and I'm WAG'ing you're either a size 49 or a 50. The down side: They're $600!! My foot measures 12 inches by 5 inches and I wear a Euro 48. You and I are in the 5 percentile of the shoe/boot world.