At the risk of sounding cheap, consider the combination I recently purchased. If I understand you correctly, you want a speaker with a rich sounding midrange but also with a good soundstage anywhere in the listening room.

Well, my RR2150 is currently working really well with a pair of Polk Audio Monitor 70s. They have FOUR 6.5 inch speakers in each floorstanding cabinet, so talk about detailed midrange - it's great for vocals, acoustic guitar, saxophone, piano. In order to get the most out of the treble frequencies, for some recordings I have to boost the RR2150 to about 1:00 like another poster said. It varies from recording to recording. But I was listening to symbols last night and they sounded like they were right in the room with me, just amazing. The Polk Monitor 70s only have one 1-inch tweeter, but it has good detail for horns. Just be careful and don't blow them out accidentally.

I also added a sub to this system, and ended up with a Velodyne VRP1200, which is not the most powerful, but it is adequate for music only purposes, especially sweet with jazz and rock.

Just my 2 cents. I know you could spend a whole lot more, but the nice thing with this setup is I didn't even need a power amp because the monitor 70s are very efficient.

Oh, and I forgot to mention, the soundstage for these speakers is about 14 feet wide, great sound from anywhere in the room. They are narrow towers so the dispersion is unobstructed. For placement, they are off the ground about 15 inches, about 12 inches out from the back wall, about 12 inches in from the side walls, toe-in about 30 degrees, and about 14 feet apart, so the intersection of the center stage is about 16 feet into the room of my 25 foot by 15.5 foot living room.

It sounds as nice as my old 2.1 system with separates, which included a pair of classic Polk Model 10s, a 180wpc power amp, equalizer, and preamp.