G'day Tony, i would like some as well, i found these a bit pricey though.
I have noticed that the cheaper tube rings suplied with my ED80, hold the scope o.k. but definately lack in the camera mount stability, in other words, useless for holding my 350D sturdy enough for piggy back shots.
http://www.buytelescopes.com/product...69&pid=1955&m=