Good stuff Eric! old boy!!...
But why didn`t you keep your 350D and get that modded?
I will be getting my shoestring shutter control and autoguide interface soon so I can understand the need to have that work with the camera, But I would be sure if you bought a cheap remote for a 40D and cut off the plug you should be able to wire it up to it like the 20D and 30D.
Have to look into the sort of plug/socket the 40D has?
cheers Gary