Sloping top tube?

Good points. I switch between drops and risers so having a frame made specifically for one would not be a good idea for me so I would need to compromise the TT, although stem lengths can accomodate but that does affect handling.

Not easy is it :-)

I think if you designed your frame with a ETT which was half way between the two. Then bought separate stems for each bar. You'd have a decent set-up.