OK, GL Breeze prototype below. A latter-version I guess; not a whole lot different from the final pack. Mainly the shoulder straps are thinner, with less robust foam (note my jury-rigged pieces of z-rest) and no blaze-orange bar-tacking. (That's standard webbing on the straps, never mind the pixel aberrations in the photo). Other differences include, most notably, elastic cord and toggle on the rear stash pocket and side bottle pockets, which was both more secure and more convenient than the final-production stretch webbing, and was per Jardine's original specs. Also, the upper ends of the shoulder straps were box-stitched into the back panel instead of the outside. And the prototype's mesh was less robust than what ultimately emerged for public consumption.
And just for fun, here's a prototype 2-person 3D quilt. Actually, it was barely roomy enough for one person, but according to legend this was Ray and Jenny's personal quilt, which fell upon some misfortune at the laundromat, was sent over to GL for whatever reason, and ultimately went out for field-testing. Photo taken at the Saufley's along the PCT in Agua Dulce.