expert researcher needed

i want to develop a online publishing website, but to be able to do this i need a ebook compiler/ creation suite of tools so that my customers can convert pdf docs etc into great looking e-books online via a web application. your task will be to search for a ready to use ebook creation/ compiler sdks i can purchase and use on my website so that my customers will have the necessary website tools required to create e-books. I will need a couple of options so i can make a comparison