For tech books, it should be quite simple to port them using the project I'm working on right now:
https://www.mobileread.com/forums/showthread.php?t=8819
I'm using LaTeX, which provide a lot of functions needed in tech books (table of contents, footnotes, nice presentation overall...). Anyone who wrote an open source tech book could easily provide such a book to Sony Readers using our website. I'll make a video presentation of how this work this evening, it'll be easier to understand the whole thing.