Honestly, as cool as Jekyll is, there are some folks who advocate rolling your own static-site-generator.

Perhaps this is something that's viable for me? I think all of my requirements could be met with a small(ish) Perl script? I would certainly need to use something like the CommonMark module to do the markdown conversion, but a lot of the rest I could handle myself?

pros

cons

short summary?

I think the bottom of this sums it up nicely:

(emphasis mine)

There are also these guidelines to help make the choice.