I am using u8glib to drive an OLED display, and with two fonts included, the final binary image is too big to fit on a 328p (32800 bytes out of 30720). Looking at the avr-gcc output, it seems like quite a few drivers are being compiled. Is this just a matter of commenting out drivers listed in u8g.h, or is that not feasible/recommended?
That doesn't help. You should just have 1 line uncommented to tell the library what display in which mode you are using. The others will not be used after compiling, so you will not feel that "weight".
This has recently been addressed and explained by olikraus, who built that library and is maintaining it.
Which fonts did you select? Maybe select a font with an "r" postfix, if codes above 127 are not required. On the wiki pages, for each font, the size in bytes is also mentioned. Based on this, you can predict and optimize the code size.