I tried to replicate the current https://twistedmatrix.com/documents/current/index.html theme with pelican:
https://judgegregg.github.io/pelitwi/ (I reused Moshe Z.'s example to make comparison easier :) )
Sources: https://github.com/JudgeGregg/pelitwi

- Creating a theme from scratch seems easy at least for the basics
- Pelican handles rst natively, so porting current pages should be doable without too much hassle

- The theme feels a bit dated maybe (but switching/upgrading theme looks simple)?
- Pelican can be used to host any static content (not only blogs) but it requires a little more work AFAIK
- I have no idea how to replicate navbar and menus on pelican (probably related to n.2)

Please let me know what you think. If in the end we switch to Sphinx, I'd be happy to lend a hand too :)
(Although I'm currently logged in the Twisted Libera Chat, I won't be able to use it for another week or so.)

Grégoire Juge