I have just purchased the latest Sound Lab M1

I think the pair of mfa 200d's on audiogon would drive the soundlab's fine as I was looking at them for my m2's. I talked with scott franklin in san jose ca to get his opinion and he said they would do a excellant job in controlling the panels.
If you go the OTL route I would invest in a pair of autoformers.

Sure is a interesting thread; for me it is pretty simple on the OTL definition; If the input signal flows only off the output tubes and goes to the speaker output jacks then to me the amp is OTL; if there is a transformer in the path it is not OTL.