I have a suspicion that the model 20a (56k) simply named a "Baritone", but with the exact same range as the model 14 (56k) named a Baritone-Treble, is based on the older or formative Baritone layout, which appears to be of an opposite handedness to the treble orientated tenors and later developed baritone-trebles.
So Wheatstone probably [economically] trialled/marketed the formative Baritones by swapping the keys over without adapting the standard EC button patterns per side; then probably within a couple of decades later had evolved a Baritone that's sides would be altered without swapping the keys, ergo because lazy people like me, but with lots of cash, would be able to advance on their ranges without much cerebral effort. Both the 56k Baritone and Baritone-Treble Aeloas (of the exact same range) appeared to be sold at the same price over the 1920s/30s, varying merely in handedness and in the slightly different outline of buttons.
This sequence of development also makes sense. Hopefully that puts the B-T [aka TED] question finally to bed.
If I ever see a picture of an actual model 20/20a Aeola (i.e. Baritone, not TED or B-T), I'd be able to tell for sure. Shelly, can you post an image or the serial No. of your supposed TED?
ps: I don't know if similar developments have occurred in reverse at the high piccolo end of the spectrum, but that's not for this post, which is discussing bass clef matters. My hunch is that the EC is really centred mostly on middle C being on the LHS, hence the eventual need to evolve a hybrid Baritone.
Edited by kevin toner, 26 June 2012 - 05:44 PM.