Mixtes with the extra twin rear stays (and other non-mixte style ladies frames) DO come in various sizes, but the range is not great, at least not at the upper end. I searched a LONG time trying to find a mixte for my 5'-11" wife. Usually the frame sizes are in this general range: 17", 19", and 21" c-t-t at the largest (not even easy to find the 21's).
26-inch vs. 27-inch wheels will also make a difference in virtual "standover" height and overall "feel" of the bike. Virtual "top tubes" on mixtes are short, and even though you could buy a smallish frame and get a mother of a long seat post and raise the bars with a Nitto Technomic stem or some such, the overall effect is not likely to be good, as the super short virtual top tube will make the unnaturally small frame feel cramped to a tall woman. I know because I tried that route and failed. Miserably.
If you could find a 21" built for 27-inch wheels you might make it work for a 5'-10" gal. But I'm not the final authority on sizing mixtes, to be sure, so perhaps others have views.....
Definitely feel for you, though!
Best of luck.
Whitewater, Wisconsin US of A
> Hi - girlfriend wants a vintage mixte bike with all
\r?\n> the bell and whistles.
\r?\n> Been checking various miztes out on ebay and i
\r?\n> notice they don't often list
\r?\n> frame sizes for them. An old catalog i have for
\r?\n> Peugeots list their line of
\r?\n> bikes and the various sizes each model comes in
\r?\n> except for mixtes. They only
\r?\n> list one size. Was that it?? One size fits all in
\r?\n> mixte or do they come in
\r?\n> different frame sizes the way racers do? She's 5'
\r?\n> 10" with really long legs
\r?\n> and i don't wanna get something if its not going to
\r?\n> George Elanjian (Los Angeles)