One of the things I would like to see here is a thread showing actual bike measurements so I can make a guess as to how I might fit on them. Here is a sample of what I would find useful for my 2006 1/2 Downtube VIIIH. Aluminum alloy frame, stock Kenda Kwest 65 psi tires (40x406///20x1.5 front, 47x406///20x1.75 rear) This is the stock bike setup before I made modifications.
Here are the metric conversions. Both measurements are approximate, good to about 3mm.
10 3/4" = 275mm, 13" = 330mm, 16" = 405mm, 22" = 560mm, 23 3/4" = 605mm, 40" = 1015mm, 41 1/2" = 1055 mm
The Dahon site seems pretty good about posting frame geometry, but Downtube doesn't and I keep trying to guess if I could fit on a Mini. Don't have a clue about how I would do with a Brompton, Raleigh 20, Swift, etc.
I would like to encourage others to post similar pictures or even just a list of measurements. Folders are a problem because standard measurements like seat tube and top tube measurements don't really apply.