OK, to write up how this issue played out: I ordered a Selle Italia Diva, after reading a lot of the threads here and guessing what type of saddle was most favoured by those who appear to be built similarly to me. I was debating between the Diva and the Lady models.
The SI Diva was immediately a huge improvement, but still to get to the point where I'm not being squished after about 90min riding took a bit of adjustment. In particular taking the nose down mm by mm makes quite a bit of difference. I'm *still* fiddling with front/back.
I've not yet reached the "I don't even feel the saddle after a while" state, but for the rides I do, it isn't bothering me (and for the first hour feels awesome).
Chris - formerly of Heidelberg, Paris and London, now of Fairbanks, Alaska
2011 Kona Sutra 49cm - Selle Italia Diva
2009 Specialized Rockhopper Comp Disk 15" - Specialized XC Body Geometry, 143mm