Speaking of, this is what I shot with, soon to take my brothers old rig.
This is the cheapest of the cheap housings, just 600 bucks (trust me thats a steal for a housing)
This is my brothers set up, a much more expensive machined housing with the most perfect glass you will ever see in the dome port
There are ways to make a 5D fit in this housing (its for a 10D) but certain controls don't work etc.