Powerful, smallish floorstanders with high WAF?

@bodotes mentioned Larsen 8. Note that Larsens are one of the few speakers designed to go against the wall rather than pulled out into the room. Depending on your situation, that could really help with your room aesthetics.

As you go up in capability and power, it's hard to keep the speaker footprint small. I have the active version of the ADAM Audio Classic Column Mk3. It's relatively slim (9" x 12" footprint) and doesn't call much attention to itself, but can fill a whole house with the presence of live music, and the bass is strong down to 30Hz. There's a bass shelving control if you want to move them closer to the walls.

I've heard the Larsen loudspeakers and agree that they have a high WAF.  They are designed to be furniture first and audio gear second.  They have a very 2 dimensional image and cost far more than I think they're worth.   Mostly sold to people with money who "want the best" because can afford it, but also want it to look like furniture.  Goes well with your McIntosh stack.

Not sure if they're still available, but there was a pair of Joseph Audio Pearls for sale here that are not too big, very nice looking, and will sound substantially more muscular.  If not their Perspective speaker would also be worth a hard look.  Best of luck. 

Salk Sound has a terrific small speakers.  For instance: http://www.salksound.com/wow1%20-%20home.htm or
http://www.salksound.com/veracity%20ht1%20-%20home.htm
I was one of those SMAC members looking for a subwoofer.  
Also, SoundSmith has a great set of small speakers I was totally impressed with!  Either the Dragonfly : http://www.sound-smith.com/speakers/dragonfly-stand-mount-speakers

Or the Monarch: http://www.sound-smith.com/speakers/monarch-bookshelf-speakers

Thanks for all the great tips, guys.  Really helpful.