Yes, we would love to have more fiction authors self-publishing their books and stories on Leanpub!
Leanpub is popular with authors of "technical" books because our ability to support in-progress writing and publishing, and setting up our indie publishing platform so books can be instantly updated, are powerful tools for people writing about cutting-edge and constantly evolving subjects.
But we would absolutely love to see more fiction on Leanpub! We think a good model for self-published or indie fiction authors is to write and publish your novel or story collection in-progress on Leanpub, and then when you're done, you can and should try distributing your book through other book distribution channels, including Amazon.
For a high-level discussion of our approach to writing and publishing, with a a lot more references to nineteenth-century fiction than to programming books, please see this talk by Leanpub co-founder Peter Armstrong: