Apropos this discussion...
A couple days ago, I saw a woman on a bike setup as I have sometimes done when the sort-trunked rider wants to keep a bike with too-long top tube and drop handlebars: Reversed stem.
It sounds radical (it is) and aesthetically horrible ("different" is a better term), but it can and has worked in my experience, provided a couple conditions are firmly observed:
1) Even with a reversed stem (i.e. one installed so the clamp points backward instead of forward), the rider's preferred hands-on-brake-hoods with drop 'bars still has the rider's hands ahead of the steerer axis.
2) The top tube slopes enough to allow the 'bars to clear the top tube throughout its axial travel. Obviously, this works best on a mixte or step-through frame. For years, almost all mixtes available stateside had very long virtual top-tubes, thanks to clueless designers and a reluctance to design with appropriate-sized wheels to prevent massive toe overlap otherwise.
It also helps if the reversed stem is very short; I managed one with a reversed 50mm extension, the other used a reversed 60mm.
1) and 2) only applied in a couple instances where the riders -- both female and short in stature with trunks and arms relatively short for their overall height -- had bikes that were too long in the top tube but for reasons of attachment or financess just *had* to make the bikes work.
"Work" they did, and very well! Though I was too big for their bikes, a short spin around a parking lot revealed no handling problems and all felt normal -- again, provided I respected Rules 1 and 2 above.
'Might help someone else in a similar situation, keeping the caveats firmly in mind.
Also, drop handlebars are available with differing amounts of forward reach as well (between 'bar-tops and brake hoods) and this can easily vary by as much as a couple centimeters and is quite apart from stem length. I went from anatomic drops with the brake levers mounted high to compact drops with the brake levers far forward and a shorter stem when I faced the very similar issue of running the 590M Nomad (following the 560S Sherpa) with drop handlebars. Yes, the top tube on the Nomad might be considered "too long" to comfortably run drops, but the short-reach stem and short-reach compact 'bars have done the job nicely for me and I am comfortable and in the correct position for my needs.
Best,
Dan. (...who thinks "custom" is nice, but sometimes y'gotta make it fit)