I'm pretty sure I remember that Gold Line's 5.1 test disc has at least a few 7.1 channel test tracks. I did a quick Google search and couldn't find the track listings, but SV&C seems to concur -- and list a few test essentials you may not be aware of.

Get the test dics you need from the creator of it all. http://www.opticalstorage.philips.com/about/products/testdiscs/catalogue/index.html