Seeking full range single driver speaker recs

Some good suggestions might be
Cain & Cain Abby w/ Fostex drivers

If you are into DIY, you could do a similar cabinet called the Voigt Pipe with Lowther drivers.

These are called "full range" speakers, but they actually omit the lowest octave from 20Hz - 40Hz. Most users don't mind this, but some use subs in conjunction with them.

They can both be driven with a couple of tube watts, and don't present any difficult loads for tube amps.

I'm sure some other folks will have more suggestions.

Manger is not really qualified as a fullrange driver, even in the looser sense. It only responds down to 80Hz, and all the Manger speakers have a woofer, or use a separate subwoofer. If you plan to use the sub anyway, then they might be a consideration.

They are a very interesting design however, and I had some interest myself in them at one point. But the low efficiency was not suitable for my system. Quite expensive too.