The 0.8.3 version significantly improved MobiPocket and OEB support and 0.8.4 adds interface localization (i.e. labels provided by language specific .xml files). On the Iliad, the localization capability can be used to shorten the config tab labels so that all the tabs fit on the screen, and that in turn should allow user-specified keybindings. I have confirmed on my PepperPad that editing /usr/share/FBReader/resources/en.xml changes the tabs (e.g. I replaced value="General" with value="Gen." and that became the tab's label).
So, this is probably a good time to update FBReader for the Iliad.