Are you telling me you can get 11 kph in the Pripet Marshes? Or are you telling me that enemy divisions are hurt more by bad terrain than AC divisions?
I ask because I never seem to be able to get overruns in the woods, forests, marshes, and cities, despite my best efforts (but then again, I'm not the best at optimizing for speed, either).
No I am afraid you will not get something that fancy. However, I looked at it at some point and as fare as I remember, with 2 ACs in an Marm division you will be able to traverse the marshes at apx. the same speed as a marine division would. (depending on tech level and focus ofcourse). In other words the addition of a couple of ACs will allow a Marm division to always have comparable speed to the first best choice for the terrain in question.