Agree entirely Woz re the Eldridge Grade and lower Marin frames - the nickel Team Issues and the Ti were much more stretched - I seem to remember just over 23 inches on the 15.5 - or 59cms. I think I compared it to the Palisades Trail, which was nearly 2 in shorter in the TT. The Teams also were a much more lively tube set, which lacked the dead feel of the lower end Chromoly Marins.
Now that is good to know, something interesting for me to try one day. I assume you must measuring seat-tube center to center there?
18" Airborne (c-t actual seat-tube, c-c 15.25") virtual top-tube 22.99" so extremely close. I'm 1.73m but with monkey long arms which
I need to find some space to put somewhere. Getting longer stems to sort out reach is rarely the good answer, especially as I like to keep
to a 5 degree bar sweep for wrist comfort. As for in-line vs lay back posts, it really depends a lot what your favorite saddle was intended for.
If I was to go custom for a general purpose all day lively rider something like a 71 degree head-angle long-ish top-tube into a slacker 72
degree seat-tube with something like a 42.25" wheelbase and a touch lower bottom bracket around 11.5". An extra inch slapped on
the top of the head-tube height compared to retro, something like 5.5". For 26" wheels. Obviously.