Guy, I will pass along your information to my work crew: brother in law, sister, brother, nephew, cousin, whoever I can wrangle with the promise of a good meal on Saturday night and swimming in the spring fed lake two miles away on Sunday. I probably wouldn't have thought about putting the bow up, but it makes good sense.
They say a picture is worth a thousand words. Knowing that doing a hand sketch would have taken about 5 minutes but I have no way to get it on the computer ... I booted up Sketch-up and drew up the basics of what we're talking about building. Of course, all things depend on what is available to work with and the kind of help that shows up. Four people can do 2X the work of two people working twice as long. Anyway, the cut out in the hill is about 30 feet east to west. On the east side there is a notch (defined by trees) that currently is about 6 feet deep and 15 feet (north to south) long. The west side is a long gradual slope into the current drive area. Terry would like to have 30 feet of wall there too.
The upper level on the east side is for storage, but should be large enough that two people can sleep there. A barn ladder for access, with a work bench and RMH of some sort below. A shed roof will top it all off. The walls will go 12 feet in the back, or until we run out of logs. The front opening should be somewhere around 8 ~ 9 feet in height and wide enough to drive both large pieces of equipment in at the same time. The cut out height is about 8 feet at the back right now, and the priority is to get the walls up at least that far and backfill as needed. I am flexible about the whole thing; all sizes are approximate and I could change my mind if something better comes along. We haven't talked much about door options yet, though I'm sure the subject will come up between now and October when we need to be able to use the space for winter.