If the book is published by an actual press (i.e., not self-published), you could try contacting the publisher and see if they would print special copies with dyslexic fonts.

Likewise, you could ask a library to scan the book and do OCR (optical character recognition) on the text, and then modify the font to dyslexic via Adobe (or similar). This is, in effect, the same process a blind friend of mine uses to make braile books, though he's invested in the scanner and everything himself. Granted, this method would then require you to read on an eReader like Kindle or Nook.

I do think, if you want a great deal of flexibility, getting an eReader is the long-term solution.

Final thought: A library may have good resources available for this, and I don't know a single librarian who wouldn't bend over backward to help someone that wants to read but who has a disability.