"Don't dismiss recumbents - seriously."
I don't! I've had a couple! And I am sure that many 'bents are ideal for those with e.g. back problems. But I have none - I doubt I'd ride really quite rough off-road on a rigid if I had. No, it's just swinging a leg over the saddle that is beginning to be a bit of a chore.
It's occurred to me that adjusting my "mounting" system is a good if interim solution - especially for steeply sloping top tube but diamond frames (like my Dawes Synthesis), on which if I slghtly lean the bike I can step over the top tube rather swing over the saddle. Swopping my mtbs to smaller, more extreme, modern, frames might also work in the short term.
I do think that in the longer term true step throughs will be the way to go (and I also actually like the aesthetics of mixte frames).
I don't think I'll be going Dutch!