I've contacted both publishers and authors in the past. The publishers don't always respond and when they do it's usually some generic response (in my experience). I recall several of us getting the same response from Penguin even though we were asking about different books.
One author I wrote to responded that she wanted to get her books in digital form but did not have the rights and more and her hands were tied. That was a couple of years ago. Now all of her books are in the Kindle store.
It can't hurt.
