Probably not a solution for your problem, but Michael Bedesen has a program that adjusts the line length of text files so they will fit on PSR. All other brands, as far as I know, have automatic wrap-around text feature. If the line doesn't fit, it puts the rest on the next line.
You could put the entire song list in a text file and then you would be able to change the font size, but the songs wouldn't be "clickable".
I have one file with a list of my favorite, memorized songs and another with a list of customer favorites, with name of customers and their favorite songs.