> I'm thinking now of putting the third-party Ruby files into a local 
> subdirectory of the installed code, and munging the load path in my 
> code, prior to calling require, to add this local directory.  If the 
> user already has mime/types.rb, great, the global version gets called. 
> Otherwise 'require' should be able to find the copy installed in the 
> relative directory.

Speaking as a packager, don't. Just document, clearly, the dependencies
and where to get them. 

It's annoying to have to patch away the extra cruft when packaging a
package for distribution with a linux distro -- but that's the job --
make it as light as possible with all the features.

Ari