Unless you get a custom job, a frame with a seat tube as long as you need will have a top tube that is proportional. Top tubes can only get so short, anyway, before toe clip clearance is an issue. Even going to 26" wheels might not be good enough. That's why WSD Terry Bicycles use 650B (24") wheels on their very short top tube designs. I don't think you have to get that radical. What i would do, if it were me, is get an upright bar that has a large amount of back sweep. North Road Bars definitely qualify, check out the Velo Orange North Road Bar, but other bends can offer huge amounts of backsweep and considerable amounts of rise as well. But be certain that you really need that much accomodation. "relatively long legs and short torso" is how a lot of women describe themselves. A bike fit website requires much more precision. To really do it right, someone else has to get up close and personal with your body and a tape measure. The person who could do that for me is blind so I make do with less precision than is perhaps ideal. Also, could be the angle but... your seat does not look level. It should be. Any deviation from level should be with a 'nose up' aspect. No more than a few degree's though, a little goes a long way. If in doubt. Dead level.

H

According to Sheldon Brown, 650B lies between 700C and 26", with 700C having a BSD (bead seat diameter) of 622, 650B having a BSD of 584 and 26" having a BSD of 559. Measuring Bicycle Rim Sizes

Thus, for reducing toe-overlap one is better off with a 26" than a 650B, but only by a little.

Terry does build some bikes with 24" (520 BSD) and with 650C (571 BSD) front wheels. And let's not even get started on all the various BSD's of tires/rims labelled as 26".

Frankenbike
 

I know a lot of you are going to cringe, but here's what I've come up with (with a few more questions):

(Also, for the record, I went to a couple of bike shops with the Surly and they all say the top tube is too long for me, but vertically I couldn't go any smaller. And after many more doc appointments, for the foreseeable future my options are to not ride or ride upright--it's not just the wrists after all.)

I found an upright steel frame with 26" wheels--this one? Fuji Sagres 3.0 LS Bike Pearl White/Gold 16in (S) for Sale - Mens want to swap at least most of my Surly components over. The two hitches I think I'll run into are with the fork and brakes (obviously).

My questions are how much I might expect to pay someone to braze on a rear disc tab? And the fork--both headsets are listed as 1 1/8", but what else do I need to look for/be worried about? The headtube length on the Surly is 6.4, whereas on the Fuji my options are 6.2 or 7.4 (I'm not sure without trying them whether the 16" or 18" frame will be best for me otherwise). I don't think my Surly fork is cut at all.

Thank you again everyone!

there may need be more saddle setback and higher, closer bars , that combination shifts the weight off your hands and onto your back side.


QBP Surly's parent company, sells the same fork as they used in the bike, then you dont cut the steerer tube down.. (add more spacers)

the assembly line project included cutting the steerer down in a formula that matches the s1ze of the frame , not the needs of the rider..

This is a very bad idea. Moving components over from your Surly will not be cheap. I'm sure you can afford it, but, why? Why pay hundreds of dollars and at the end of it still only have one rideable bike? You can buy a decent new bike outright with the savings on the now moot shop fees and welding/brazing charges and etc. and you will still have the Surly to sell or whatever. By the way, no matter what you or your doctors think, the best position for your back is supported at both ends. Sitting bolt upright on anything is not the ideal situation for backs, or wrists even. I mean, you could get really extreme about it and put a set of time trial bars on your Surly and all of your upper body weight would then be supported by your forearms and elbows. I also don't know who has managed to totally convert you to thinking that disc brakes are some kind of must have, but they aren't. Humanity got along fine before the last 5 years or so of available disc brakes for the retail bike market. Certainly one does not have to have a disc at the rear! FWIW.

H

Have you looked at the Surly troll? Seems like a fit issues. For my cross check I have my bars about 2" higher than my saddle. One of the ways for less wrist issues are a range of hand positions, either a drop bars or a flat bar with bar ends. Both work for me. I also like a flat bar with 15-20 degrees sweep.

As for the step through and 26" wheel a Beach cruiser is a good candidate to modify with wheels using Drum brakes

Sturmey Archer Drum brakes have worked well for me for 25years , in all weather .

new these days is an 8 speed internal gear hub with drum brakes ,X-RD8 Sturmey Archer

and a drum hub dynamo combination for the front. XL-FDD Sturmey Archer

the frame alterations are moderate , as the brake really does not need a frame braze-on.