I'm not sure what you're describing. On my Vapor Trail, the frame wasn't removable - it was sewn into the back pad. Did you have a defective model? (Or did they change it for 2009?)

Anyhow, I always liked the Vapor Trail for loads below 25 pounds; above that, I found it began to get uncomfortable for me (it may be that it's a fixed torso length, and the medium was a bit short, but the long was a bit long.) Anyhow, I used it happily for several years. Recently, I replaced it with an Osprey Aether 60, which I chose in response to some other changes in my gear and the types of trips I'm taking. (I backed off a step from ultralight.)

If you intend to lighten up a lot, the Vapor Trail should work for you. If you find you like the general design of the pack, but not the suspension, you might want to look at Granite Gear's Nimbus Ozone. If neither of those work, take a look at the 2009 Osprey Atmos and Exos series - the packs are in the 2-3 pound range, and made for light packing. (My Aether 60 weighs 4 pounds. Even with it, my summer weekend weight with food and a quart of water is 20 pounds; add winter clothing, and I'm at 23 pounds. Extra water adds up fast - and a lot of places I go lately require me to carry 2 or 3 quarts of water, so I can hit 25 or 30 pounds pretty quick - thus the Vapor Trail no longer made sense for me. But it's still a great pack in the right circumstances.)