You could try the lumenarc's, EXPENSIVE but IMO the best reflectors available. Both single and de available That would leave you more room for either 4 (110) vho or perhaps (4) 54w t5's.
http://www.reefexotics.com/lumenarc.htm
I am working on my canopy right now, however, I have decided to run 2 vho and 2 t5's off a 660. With 2x se 250 using the 14.5x14.5" Luminarc 3 mini.
Steve