Did you know that if you make an appointment at the Library of Congress, and if you have a reasonable purpose for research, you can not only view instruments in the Dayton C. Miller collection, but you can actually play them.
I got to play the last flute made by Theobald Boehm. It was the only one he made with a closed G# key, and it played pretty much like a Haynes.
The Dayton Miller collection also has an octave piccolo (i.e., 8va). It has a fairly crude wooden body, with keys spaced out enough for normal fingers: the pads are too close together for human hands. I'll see if I can dredge up a picture...
Groove's mentioned a couple times about making appointments to see/play stuff that a particular museum has, rather than just dropping by. I think I'm going to have to do this with my "local" Musical Instruments Museum because, when my wife went there they had maybe four saxophones on display. The "oldest" and "most unusual" was a Buescher 400 Top Hat & Cane.