Amp for Revel Ultima Studio 2s

I currently am driving my Revel Studio 2s with a Simaudio Moon Evolution i-7 integrated but am looking to move to a more powerful pre/power amp combination. I only have room for a stereo amp (I don't have room for 2 monoblock amps). My audio cabinet (recently custom made) can also only accommodate an amp 20" or less in depth and 9.5" in height (although less height is ideally needed for the amp to breathe - the space in the cabinet is only 10" high).

I'm considering moving up in the Simaudio line to a P7 or P8 pre-amp plus a W8 amp. Other option is McIntosh MC452 amp and a Mac pre-amp or Mark Levinson 532H amp and a ML pre-amp (or a mix of the Mac/ML gear). Suggestions?