hrm, my timing was a bit of a guess, I'll get a stopwatch....
22 seconds from selecting an epub in the content lister to FBReader displaying the page, down to 15 seconds if it is loading a page with little text on it.
I've noticed that font size seems to have an effect on page load times, the last page in a chapter, with less lines takes a fair amount less time to load than a page dense with text.
Anyways, attached should be a zip file with FBReader 0.11.1 with my patches. Unpack to /media/cf/Programs
Disclaimer: It works for me, might not for you etc.