@meetearl Thank you for the response to this thread. Even a short post like this goes a very long way.
While I can understand why you feel that a one handed device has advantages, I must disagree on usefulness in the backcountry. As has been stated by several people on this forum, me included, one of the big draws that earl first presented was the possibility, finally, to have a daylight readable, rugged (weatherproof), battery sipping device to use for maps, books, and all around computing (sans video playback).
That to me is one hell of a product, I jumped aboard. While it is true that most people find it very convenient to navigate with their cell phone, one handed, that is in an urban environment. My experience has been that trying to pull up a topographical map, when lost in the great outdoors, on a cell phone screen is less than ideal. The screen, even with its color and high resolution, just doesn't have the real estate to display all the map I need. I've found myself squinting at a small screen, constantly panning the map left and right trying to figure out what I'm looking at.
For years I've used paper maps, the usually required both my hands, unless I was just doing a quick check to see that I was still on course. 6 inches isn't so big that it can't be manipulated one handed (and I have small hands). Cleaver designs make it even easier, by having grips built into the frame of the device. I believe one of your previous designs employed something along those lines (a shallow depression on the back side of the device that corresponded to the horizontal holding position).
Your reply has rekindled my passion for earl. I was going to hang in there and see what came anyway, but now I have some hope that you are still open to input from your backers.
Bottom line, please reconsider your form factor, I vote 6 inches.