So, one of the users of my Image library asked if there wasn't any way of using a font other than the rather ugly, built-in one. I said, roughly, "you can define a new one, in an analogous fashion to how the built-in oine is done?"
Apparently, that was not the wished-for answer and I started thinking. Bit-mapped fonts are (relatively) easy to deal with. There's a helluva lot of bitmapped fonts for X11. So, I set forth to code up a reader for PCF fonts, converting the bitmaps to internal format and some multi- font support in Image. All done, now.
Common Lisp is still very pleasant when dealing with binary file I/O, even if I wished that there was an easy way of changing the binaryness of a file on the fly.