The GOSS gaming system from Decision games.

[Nathangun]

I came across this system a week ago. The level of detail is extraordinary. Although the rules are complicated, you don't need a PHD in mastering them.
Units are Battalion- company scale, battalions can be split into companies.

There are four games, vassal modules available from the decision games website.

Hannut 1940

Wacht am Rhein

The Atlantic Wall

Lucky Forward (Pattons drive to the Rhine)

 

[mTk]

Game estimate is 1244 turns.