I bought 2 stays from http://www.sixmoondesigns.com and attached them to a plastic trapazoid shaped blunt-edge painting trowel I got at Home Depot — that fits between the pack and the VT belt and at the top of the stays, I drilled eye hole in the stays and used 50 pound strength fishing spectra line to secure to the load lifter straps to secure the stays in the pack without hurting the fabric of the pack. (ps, I padded the top of the stays using the sticky velcro (about 3" folded in half) to avoid having the top of the stay hurt the VT fabric.
I did this in a new, long VT pack and I discovered to my chagrin the pack weighed about 2' 10 ounces (it weighs 2' 2 ounces to begin with being long). That puts the weight of the pack very close to that of the Nimbus Ozone which has a firm frame in it, and the Nimbus Ozone (weighs 3 lbs) holds more gear — ie, it holds a bear cannister sideways at the bottom of the pack without stressing the fabric.
The stays add about 4-5 ounces to the pack, but you somehow have to secure the stays to the pack without hurting the pack and that is where the few extra ounces came in.
I'm typing this from memory and may be off 1-2 ounces in total weight of pack but I think this is correct.
Bottom line, it's better to take a SixMoonDesign Starlight pack and swap the belt to use the VT belt, rather than take the VT Pack and make it as good a riding pack as one that has stays in it (like the Starlight does). The modified Starlight pack with the heavier belt is still under 2 pounds.