Why can't I find a comfortable saddle? During the 25+ years of cycling I've done (5,000 - 7,000 miles/yr), I've tried upwards of 75 saddles, yet STILL haven't found one I could call "comfortable."  By now, I know what I want, but can't seem to find it.  Firstly, I don't like any with those cutouts, grooves, love channels, etc., including those really weird ones (SMP, ISM, Adamo, Cobb, SQLabs).  Basically, I'm looking for a "medium" saddle -- another apparent rare commodity these days -- both padding and size-wise (i.e., not a hard, narrow racer, but not a big, soft "comfort" model, either).  As for padding, the closest I've had is a Terry (men's) Fly and (woman's) Butterfly.  Besides not liking the cutouts, the Fly was definitely too narrow, and the BF a bit too wide (and short).  Shape/wide/profile-wise, the closest was a Blackburn Ciento.  Also liked that the rails allowed a more rearward position (for my 91 cm+ inseam), but the padding was some kind of memory foam that I found a little too squishy.  I'm looking for about a 150-155 mm width, a flat profile viewed from the side, but a bit rounded (mainly near the sides) viewed from the back.

Could the problem be related to fit?  I'm in a moderate position (bar 6 cm below saddle, back about 30-degrees above ground when on the hoods).    I've had 5 bike fittings done, none of which I could call "comfortable" or "efficient."  Most had the bar 3 - 5 cm further away and/or lower than what I have now -- apparently thinking my position was too scrunched up -- which not only caused more rear/crotch discomfort/saddle-sore infestations, but also a 20%+ drop in power output.  (The Guru fits used the "Slowtwitch" system which -- for reasons I can't comprehend -- bases bar reach on a percentage of saddle height . . . this puts my reach a 60 cm, which is 6 cm longer than what I have now!) 

Could something about my posture be not-quite-right?  On another forum, someone said that I'm "not sitting the right way."  (Not sure in exactly what way he meant that.)

Or, could it just be that my expectations are exceedingly high?  (Yes, I know a saddle is not a waterbed or luxury recliner, but it would be nice ride without any pain/discomfort down there.)
I'd look into a manufacturer that actually makes saddles in different widths, get your sit bones measured, and try one of their recommended saddles.  Keep in mind that there may be a conversion involved.  I rode the wrong width saddle for a year because I assumed that my measurements should match the listed width of the saddle (not true, the company I prefer has a chart and there is basically an offset, ie my 137mm or whichever sitbones actually use a 143mm saddle, not the 135mm one). Here is an example style size chart.

It sounds like you are looking for a particular width, but there wasn't mention of you having your sit bones measured.  If you've done this, but it hasn't worked out for you, I'd be next wondering about abnormal anatomy.  Just like people have different length arms and/or legs occasionally, perhaps your sit bones are not spaced evenly from your midline and you might need to get some inbetween size to accommodate.  There are companies making adjustable width saddles, so that's also something you could look into.