Awesome information, all. Thank you so much for the detailed information. I am always impressed at the number of folks who can tell so much off the cuff from a few pictures. I guess I could do that on military aircraft, or old tractors, but anyway... impressive and much appreciated. The collective knowledge here is impressive, and it's far more interesting to interact with you all than dig through old catalogs (although I also do that often and enjoy it).
Whatever I get, it will have to be at least a 25". When I measure my Bianchi Sport SS from the center of the bottom bracket to the top of the metal in the seat post, it measures 27", but I don't think Bianchi made a 27" model, so perhaps I am measuring it in the wrong place. I have a Moto Grand Jubile that measures 25" to the top metal on the seat post, but it's noticeably smaller than the Bianchi, and frankly a little too small for me, though it's a very light and slick bike I otherwise am very fond of.
I think in the next wave of Peugeot design (late '70s, early '80s), I believe they made a 26" Course (but only a 25" Competition and Super Competition). Perhaps I ought to search for one of those. I've never sat on a 25" Super Comp to see if it fit. I used to have a 63 cm Specialized Allez 1 '99 model that seemed to fit fine...
At any rate, I will stop and look at that AO-8/UO-8 next time I'm up in Stockton. It's not all that far. Thanks again for the wealth of information.
David