ICOBundle
While the ICOFormat plugin creates ICO files containing a single icon only, ICOBundle combines multiple ICO images, of different sizes and/or colour depths, into a single ICO file.
Available as a drag'n'drop application on Mac OS Classic/OS X and 68K, or as a command-line tool (built from GPL source) for Linux, OS X, other UNIX variants, and DOS.
Sample DOS session
