kinda off-subject but I found something kinda cool today, and it's cheap so i'm considering trying it just to see how it feels, but it is a little hump that attaches to your bottomline threads and adds a hump to the back of the frame to make it feel like a timmy-style clamshell
http://www.freewebs.com/thehump/
It looks like it would work, but we'll see