I find that I like the look of short seat stays, as if hellenic stays were attached and ended at the seatpost. I realize that most of these are aluminum or carbon fiber, but are there problems with building such a frame from steel?
it's generally a good idea to reinforce the area where the seat stays intersect with the set tube with a sleeve. Same with the top tube. If the top tube and seat stays don't intersect close to each other, you need two reinforcement sleeves.
it's a better structure to have the seat stays meet the top tube. Many bikes have broken at the seat tube/seat stay/top tube junction. It's probably just as common as breaking at the bb and more common than breaking at the head tube.