Even for code that isn't a module

Yes. Most dists are module-based, but not all. See PerlPowerTools for example.

and (probably) isn't very useful to anyone else as it stands?

That's more of a key point. While it would be better not to clutter up CPAN with code only you will ever use, could it instead be generalised in some way so as to make it worth sharing? It may even be of more use to you in the long run if it could be made more general.