I built my first accordion a couple years ago, and getting info for that project was difficult at best, with little infomation on the web, and living too far from other builders. I started the box builders group in hopes that there could be a central place to share info on shop tips, suppliers, etc. Every pro builder I've talked to has been most helpful answering questions, and most gracious offering advice. This isn't about cutting into anyone's profits, rather keeping an art alive.
http://launch.groups.yahoo.com/group/boxbuilder/
I did build the jig you showed me, or a single bay one anyway, but then realized I didn't have the total setup to do what I wanted, then moved, then less space here, etc, so, its in limbo right now.
I did try several test frames with some plywood I had cut for the purposes of testing. I found that I consistently had the end piece that was at the back of the jig being depressed by maybe a business card thickness from the side pieces, even though things were even when I clamped it and then left it. Never could figure that out. Figured I'd just start putting a business card under it before gluing.
Now I'm busy with school and a band, so, its in limbo. I did and do appreciate your willingness to help me on that, and when that "hobby" rotates through again, as they tend to do, I'll probably have more questions to ask.