So here's another backpack prototype. I've made a similar top-loading pack before, but I made that one all screwed up...it was too long, the shoulder straps were too far apart, and it was flat-folded on top, so, despite the width of the bag, you really couldn't fit big things in it. Boohiss, I know. So with this bag I fixed all those problems. (And what I mean by "flat-folded": the lip and flap are the same length, i.e. no pleats...so the bag can't expand.)
I haven't put the intended compression straps on the bag yet...instead, I'm thinkin' I'll put some nylon packcloth or oxford round the top and add a drawcord, a la Bagjack and Jandd. I think that'll work a bit better. That's the trick with these bags: how to maintain the shape of the bag while permitting decent load size. And that's why this post is called "Wings." 'Cause that's what it looks like you have when you're wearing this type of bag. Nice... The "tension shape" of this bag (I guess that's what you'd call it: the shape caused by the strap points) is triangular, but the bag is square, so the unsupported triangles (the top corners) pull away from your back. Yeah, I guess I should just take a picture...
And, if you're interested in top-loading flap-fitted backpacks, check out these peeps: Freight Baggage, Chrome, R.E.Load, Chicago WIG, Lemolo...let's see, who else...ah, TimTimTimes2 has one... And I've seen one from Bagjack, but I don't think it's up on their website.
Strong like bull.