Rottendog's MPU had an issue with system 7 games, and they dropped support for it since it wasn't able to be resolved.

"Please note as of 1/5/2018 System 7 games(including Black Knight) are no longer supported, Rottendog is only supporting games System 3 through System 6. A parts change due to availability created a problem making it unusable in most System 7 games, it supposedly works in some, and Rottendog cannot find a solution"

https://www.bigdaddy-enterprises.com/ProductPages/RotDogBoards.html

Swemmer MPUs work with system 7 games, but I'm not seeing any for sale at the moment. They're usually posted on ebay or ksarcade.

MPU:
https://ksarcade.net/swemmer-system-7-mpu-1d-2001-133-7-w-roms.html
ebay.com link: Williams System 7 MPU RED MASKED NEW

Driver: https://ksarcade.net/williams-system-3-7-driver-d-7997-swemmer.html

System 7 sound boards:
http://pinballpcb.com/products/
https://ksarcade.net/wms-system-6-7-sound-w-speech-swe.html
https://ksarcade.net/williams-swemmer-6-7-sound-d-8224.html

Another possibility for MPUs: https://www.pinball-dreams.com/flipper-pinball-flipperautomaten-modding-shop/verschiedenes/all-in-one-nw7.html

wow, had anyone tried the French All in One Board with Sound Board Built in?

https://www.pinball-dreams.com/flipper-pinball-flipperautomaten-modding-shop/verschiedenes/all-in-one-nw7.html

I'm curious how they are!

I have a RD combo in Time Fantasy, Jungle Lord and Barracora with no issues. Black Knight is the major culprit, and of course, they most common System 7 by a mile.