I just layed my mobo at the bottom of one crate and screwed the cards into the crate using this thread/picture as kind of a guide. as all milk crates are different my was modified a little, had to make some holes to fit cables through. https://bitcointalk.org/index.php?topic=163306.0
Yeah these cards seem to be hit or miss with what you can push them to. I can only push my card to 975mhz/300 memory before it starts crashing but my friend can push his card to 1030mhz/300 memory.