There is no MF RF with interchangeable lenses with a bigger max app than f/3.5, that I can think of.
The Paubell Makina has a 2.8 80, but its fixed
Mamiya 6 is f/3.5, that's as fast as it gets, and its only the 75, the other 2 lenses are f/4 & f/4.5
Bronica RF is a 45 f/4, even your 7 can't beat the 6 with an 80 and a 65 f/4.
All the Fuji 645's are f/4 or smaller, unless one of those zoom jobbies is faster at the wide end.....I dunno..
GW690 is a f/3.5 but again its fixed..:shrug: