Not sure how that helps any, prob because it doesn't
I was going to let this slide without a mention, but what the hell...
mctrav, that tone is not going to do you any favours. That is how you respond to someone who is antagonizing you, not to someone who just provided you with multiple helpful leads.
No hard feelings, it just came off as rather dismissive to me - I thought the post you were referring to was quite constructive and on topic...
There are legions of guys (including most of the people on these forums) that spend countless hours tracking down these vintage tobaccos and many of them are first in line for the hard-to-get blends from the etailers and consignment shops because they have signed up for notifications or cultivated relationships with the owners.
Even the odds of you walking in on a motherlode of aged tobacco in some dusty B&M slims every day as people are becoming more informed about what is valuable and what is not, what is well-acclaimed and what is not... It may still be possible in some parts of the country but by and large somebody has been there before you to retrieve the "gems".
rmbittner has the best advice here: "That's my round-about way of saying that if you love a blend, stock up; don't wait for it to make some list of 'fabled' blends that are hard to find."
In response to your question, though, the others have answered it pretty well. Samuel Gawith and Esoterica lead the pack as far as rare still-in-production blends go. Discontinued blends are probably too numerous to mention, but everyone has made a valiant effort of it for you so far...