One last post for tonight, after my epic (and successful!) quest to Philadelphia today.
I reported back on January 31 that the JH Preferred card had some limitations that some of my more enthusiastic blogger brethren had overlooked in their original reports. Namely, unlike their "direct" competitor, the HR Block Emerald card, JH Preferred doesn't allow ACH pulls from the account, which makes it simultaneously less convenient and more expensive.
After patiently loading my JH Preferred card up with $5,000 in Vanilla Reload Network reload cards, I ran into yet another limitation: my usually-completely-reliable local Bank of America branch was unable to process a cash advance for $4,995 (why $4,995? There's a $5 cash advance fee, and I don't have any interest in trying to rip $5 off from Bancorp).
I'm not willing to rule out user error on the part of the teller, but I do want to share my experience so my readers aren't unduly surprised if they're not able to liquidate their JH Preferred cards in one go. It may still be worth trying, if you have a bank branch willing to help, since there are a few reports of successful $5,000 cash advances in the relevant Flyertalk thread.
I was ultimately able to liquidate my $5,000 JH Preferred balance by making 3 Walmart PIN-based debit transactions, so don't despair if your cash advance attempts end up not being successful.