I love this! Your setup looks really similar to my shop - except better organized. I even have a window in about the same place, the lumber rack above, and a radial saw to the right of where I plan to put the LongMill when it arrives.
The radial already sticks out about 36" from the wall, but my shop is kind of narrow and adding another 12" or so on that for the LongMill is going to make it feel even more crowded. This looks like a great solution to that problem. Folded up it would be no wider than what I already have, and when folded down I can just deal with losing a little floorspace temporarily.
Do you have it on wheels? That would be perfect because then it could be rolled away from the wall to do longer stock too.
Are you planning to publish your plans anywhere?