There is a converter that allows to convert various types of documents and ebooks to LRF format.

I didn't try it but it can be useful for someone - http://www.lib2go.com
Supported input formats are: DOC, EPUB, FB2, HTML, LIT, MOBI, OPF, PDF, PRC, RTF

It's annoying that they use calibre and don't acknowledge it

EDIT: Nevermind I see that they do

What a Shame!

Thanks again Kovid!