There is once again hope of finding the featured/promotional books for the Kindle, in the sea of public domain books! This search sorts them so that the featured books are listed first (it also appears to show any free blogs, so I suspect it will show free magazine or newspaper issues, if they exist):
FreeOnKindle
I have even figured out how to completely exclude the public domain books and set up a second search for that one:
KindlePromotions
The first one I set up limits the list to free (zero dollar) Kindle books and sorts by "promotions/features". The second link also excludes the publisher "public domain books" and right now gives you just 12 books (the current freebies). Hopefully in a few days those 16 Harlequin books will join the list.