I've seen live compilations of 'Hot Space' and now 'A Night At The Opera' be uploaded; I think it's good to see this.
One of my other favourite artists is Springsteen and one of his messageboard sites (SPL), the bootleg collectors have compiled a set of CD's comprising of the BEST live version of the album tracks.
Basic information can be found here link
The example of the process of deciding songs can be found here link
Wouldn't it be a great idea if the collectors from this board could get together and start compiling these sets?