The awesome thing about eBay is that tons of prototypes pop up for sale that never make it onto the internet in any other way, that could potentially disappear forever if not for attentive collectors.
Looking closely you can see that this pack is a missing link between the MOLLE II ruck and the FILBE, It has the full MOLLE coverage like the FILBE but lacks the waterbottle pockets, it has the seam-to-seam sleeping bag zipper like the FILBE but the lid of the MOLLE II. It appears to lack the reverse pull waistbelt of the FILBE, and the shoulder straps themselves have more in common with the MOLLE II then the FILBE. This pack does use the smaller airbourne frame and attaches with the ALICE-style frame sleeve, which in this case is much longer and covers the padded panel the shoulder straps are attached to.
Always interesting to catch a little glimpse of the process.