WOO HOO! I found the Tank Slapper kit I lost about two years ago. I ended up buying a second one and so this one is now surplus.
$20 for one of the True Brothers of Green.
This is probably THE best way to protect your tank from scratches in the paint from your knees and jacket zipper It also includes a small "bib" for around the gas filler to help protect from tank bags or clumsy gas nozzle use.
You can read and see (or not see as the case may be) about them at http://www.thetankslapper.biz/ .
It's a static cling style of plastic so there's no glue to clean away. But they stick really good for a couple of seasons and then you'll find small pockets of dirt forming around the edges. Peel 'em off and wash well along with washing the bike and then squeegee them back on and you're good for a couple of more years of protection that literally looks like there's nothing there at all.