I've been looking at the source code for fbreader to see how they make their configuration editor look so good. I haven't seen anything that looks obviously different, but I see that they provide an icon for each entry, something that I never tried. Perhaps the size of the icon determines the size of each line, which determines the size of the font used. I'll play with this later to see if it works.
I got the fbreader source code from here: http://sourceforge.net/projects/pocketbook-free/
Edit: It worked like a charm! I copied over the images.c file from the fbreader source code, referenced one of the icons in each line of my iconfigedit array, and compiled and linked in the icons into the program. The configuration editor screen now looks as good as the one in fbreader. I'll need to use an appropriate icon for each line, but now I know how to make it look good.