Interesting forum and all you sufferers have my sympathy; we runners tend to think we're invulnerable until we get injured and then that we'll never be able to run again.
The general tone seems to be nothing much works, and this may be true, in its very name Plantar Fascitis, it states the problem, this is inflammation of the plantar fascia, which is why anti-inflammatories like Ibuleve can give short term relief, but may not cure the problem.
The best cure may be simply rest from running until the condition settles down, which, of course, is what we runners won't do! We look for a treatment that will stop the symptoms while we continue to train, which may be why most treatments fail and the condition lingers for so long!
As a TCM Acupuncturist I have treated PF both on myself and other runners, usually 1 session, or at most, maximum 5, and problem is solved, though nothing is guaranteed of course.
Is a technique using a TENS machine on fluctuating wave length on two points, Bladder 57(or 58) and Kidney 3, after obtaining qi on both needles. Patient should feel a vibrating/tingling effect, not where the needles are but under the heel at the sight of the PF pain, and then this should last at least 1/2 an hour to an hour, the longer the better!
I appreciate this is not much use unless you know a good Acupuncturist but any BAcC registered one should be able to replicate this treatment - whether they will do so of course depends on their ego and how good they are with a TENS machine. I would probabaly avoid drop in centres unless you have no money worries (they may recommend a course plus herbal medicine costing a lot), and if you get no appreciable change in your pain levels further treatments may have no more effect than the first!