I think so too, but if even providing a script is too far then just provide an easy mechanism to preload kernel modules before the installer runs.

It seems like literally something as simple as defining an extra directory on the installation medium for which all files will be loaded into the kernel at startup. Or allowing the installer to be started from a live environment, so you could download/build sources and load the module and then start installation.

Perhaps it can't be Canonical who actually writes and maintains the script, but it seems like a problem you could hack around fairly easily while maintaining plausible deniability.