..Has anyone else ever played one of the older chanters that used a d# key for the right pinky? I’m curious as to your observations re: comfort of playing and tonal quirks.
First of all, the ‘e’ key was played with the index finger, unless you were holding the chanter upside down… 
only the Bb is ever played with the left pinky. This is the ‘e’ key for the note in the third octave you’re talking about, right? On the front of the chanter, above the C# fingerhole. They’re nice, very solid note, if you’re going to hang out up there a lot. You can also do a kind of diabolical trill on the back D, since the tonehole is slightly higher up on the chanter. They need to be small, though, short and narrow or your C# finger will collide unexpectedly with it. I played an Egan chanter with one, it was very dainty.
Or do you mean the low D# key? I had a chanter with one of those beasties, too. Those seemed about equal in volume to the usual Eb when you were done. You could also get a vibrato on the hard D with one. Shudder…
Kevin, the d trill with a high e key sounds like an excellent idea. You’d certainly have a lot of people scratching their heads if they were just listening to a recording. Sounds like one of those nasty little tricks of the old pipers to stay ahead of the pack. 
djm
ruh-roh! 
heh! Yep..I did indeed mean the low D# key (brain fart!)
I had a new chanter with one, a bit too long a key so I had it shortened. The old ones I’ve seen in pictures don’t look like they’d be in the way at all. Mine sounded like your typical keyed note for volume and tone. I forget how drastically improved the pitch was. About the only guy I can think of with an oldie with a D# key is Nollaig MaCarthy, who teaches at NPU, and now plays the “Busby” Coyne B set, perhaps you could email them and they could pass on the question.
I’ve been away. A bit late with this maybe but my B chanter by Joe Kennedy has the low ‘E flat’ key.
It works best for me off the knee, definately with the ‘not hard’ low D pressure. Of course I don’t use it at all.
Regards, Harry.
NPU also have their message board where you can post your question for Nollaig at http://www.pipers.ie/discuss/
It’s worth a shot??!??!
Patrick.