Is there a monitor speakers with just one driver?

tannoy also makes one-driver (dual concentric) monitors in the "saturn" range. -cfb

I think I understand the question, but I would also point out that for most practical purposes, any midrange driver is a full range one, it just can't reproduce the extremes without help(Bose, and it still nee, never mind)Given that, if all you are going to use this for is midrange,IMHO, you should be looking at a quality midrange driver, or some of your small studio monitors. I still forsee incredible problems with with output matching and driver blending. Maybe if we knew the exact application we(I) would understand it better.

Lowther drivers are full range -- but they need specially designed cabinets to work well.

http://www.kef.com/qpoint2grp.htm

My favorite full ranger is the Fostex. Either 108Sigma or the 168 Sigma. They make sweet music but like most full rangers suffer on the bottom. Good thing is they are cheap (compared to some of the Lowthers) and there are plenty of good designs available in the public domain.