Can OTL's drive ribbons well?

"fast organic liquidity with dynamics at around $4000 and hopefully much less(new or used)-- again specifically driving ribbon mids and highs?"
I don't know what associated equipment you were using with the bryston maggies or what your musical tastes are. I was listening to the Mark Levinson CD 39, 38 preamp bryston 7b and the ribbon tweeter maggies. The CD was Branford Marcellus duet with his father. So good that the salesman went out and bought the cd.
I think the 7b's were about $4k.
If you want to go all out like the $10k-27k atma spheres'. We can have a shoot out tube vs solid state.
If you pay attention, I have nothing but praise for the atma spheres. Wouldn't mind owning them myself. Those tubes must produce a beautiful glow at night. I just think transistors offer more speed than tubes. If you don't mind the softened transients of tubes please be my guess.

Berning did a presentation several years back to fellow Physicists at a convention, where he proved that tubes measured faster than SS devices, so much so that the SS measuring device that was used, showed the tubes was faster than the measuring device was supposedly possible to measure!

None of us listens to a tube or a transistor alone; It's the implementation, i.e. the amps, we listen to.
One good thing about tubes is that a circuit can be stabilised w/out feedback thus eliminating extra "length" in the signal path. Another is that, given the lowish output in these circuits, one can build a tremendous driving "engine" (i.e. trannies & rectification and energy storage) to accommodate those few watts.
As Eldart pointed out, tubes can easily go into the MGh region just as transistors -- they just have high output impedance to drive devices like spkrs directly (unless you parallel them & then some, see OTLs).
Likewise, a transistor amp, designed to cover a wide bandwidth should do well -- as long as it doesn't have severe phase problems (i.e., the time window for a 0,5MGh signal is much smaller -- i.e. you have to rise & fall faster in time -- than, say, a 500Hz one).
BTW, if I'm not mistaken, Mr Berning doesn't use output trannies in his basic designs...

I have driven my Magnepan 3.6's (which have a vertical ribbon driver) from the Atmasphere MA-1's and the MA-2's, both with and without the auto-transformer. To make a long story short, the sound is spectacular with the auto-transformer. It is detailed, liquid and without any grain or harshness. It is a superb match and without introducing any anomalities. Without the auto-transformer the sound is still excellent but, the response is a bit uneven. There is a little bloat in the midrange and, perhaps a slight downshift in the extreme treble. This is more true with the MA-1 than MA-2. No doubt this is due to the rather significant internal impedance of the amplifier starting to affect the overall speaker crossover impedance.

Genesis ribbons are fairly stable 4 ohm loads with a bit of trouble in the 85 to 200 Hz area that is taken care of by the crossover. OTL's might not be the best choice because they are designed for 8 to 16 ohms, usually. Some of the bigger Atma-spheres have no problem with 4 ohms. One thing to consider on the OTL's is the cost of retubing every few years. There are tube amps, like Manley that are designed for low ohm loads.

I have heard people swear by both SS and tube amps for the Gennies but they all say they like lots of power. Not sure if speed is an issue but tubes usually have a slew rate much slower than SS. Edge and Monarchy make some of the fastest nowadays.

http://www.atma-sphere.com/papers/myth.html