So here's the deal:
I love the uber cities I can make with Sid's Sushi + Mining Inc. I also like the terra map script, which gives so much sea food I'd be crazy not to use them. However, as an aspiring dictator and dedicated socialist, use of the "free" market civic is anathema. So I have decided to restore SP to it's rightful place as the best economic civic option in the game. I say, equal share for everyone!
(Idea for mod name, ESfE)
For each grain/seafood +x

per city
For each copper/iron/coal +y

per city
For each gold/silver/gems +z

per city
Of course, it will be smaller than what corporations would yield, but it's free.
My first idea was to modify SP itself to give these bonuses.
Today I thought about maybe trying to make it a pseudo-corporation that is allowed to run only under SP.
Another idea would be to make it a religion that is founded by communism tech, but it implements the yield modifying methods used by corporations, or give it a "temple" (☭ party office?) that does the same. (Tomb of Lenin as shrine? No idea how to do graphical stuff.)