If you're not using both drive cages you can string the rad in the 5.25" bays, if the tubes reach(they're about a foot long).
Between the H80 and the H100, cooling performance isn't drastically different, 3 degree difference p/p on my 2600k.
Unfortunately I have six drives but perhaps I could put a few in the cage in the top/rear of the case (would need longer sata cables than I currently have).
Would a radiator stand be preferable with such a configuration? I wonder if the 12" lines would be long enough. I'll have to take some measurements.