I don't have a kindle yet but I can't imagine why (an unfortunate turn of phrase mayhap) RMc's work wouldn't be there. Sad.
Hunter may know what's up with that.
For some of the books, they're not available for Kindle because Pocket Books currently holds the ebook rights, and they're not interested in releasing them as ebooks (yet, anyway). They're the ones to thank for The Queen of Bedlam being available for Kindle, but not Speaks the Nightbird.
Ebook possibilities for some of the older titles are being investigated....