Can single ended 211 or 212 amplifiers drive magnepan 20.7?

No direct experience with the Maggies, but having a sensitivity of 86 dB...I wouldn't think what you're proposing will work, either option.  I once drove a 90dB set of speakers with 60 watts of (KT88) tube power.  Sounded..wonderful..but volume-wise..I could only get to moderately (low-ish) volume.  

By all means pursue the Maggies, but you'll need a tube preamp and some real power.  My current system, due to change completely in a couple months, runs a tube pre into a McCormack DNA1 power amp into 86dB speakers. It totally works. I've enjoyed this system for 10+ years..no complaints.   

@kennymacc hahaha exactly right! tubes for tweeters and mids, large beefy solid states for the bass! 

@lcherepkai oic, will go take a looks at your speakers and amplifier! thanks for sharing the experience!

@nogaps actually i have a different experience hence i am asking about this. haha my 25w cary monoblocks have no issues powering my 90db kef reference 5s, and I really love them. I also hahe a dali minuet se that is 86db in my bedroom powered by 7w 45 tube push pull amp. Both have enough volume to satisfy me :) I listen at 80-85 db levels. 

@thegreenman An SET based on a type 45 power tube might make about a Watt. Certainly not 7; if your amp really uses 45s and makes 7 Watts, its push-pull not SET. 

But to be clear on your original post, no SET made will drive Maggies. But FWIW there are class D amps now that compare favorably to SETs that will drive Maggies no problem.