The Close Combat series tried out various different operational map systems. There was MMCC III which only worked with CC III and Cross of Iron. This had the advantage of a very, very large number of maps but was otherwise feature-poor. It was based on squares but diagonal movement was allowed, and because of the way the deployment system worked the enemy could appear behind you and beam itself across major obstacles, like rivers. The other system was better thought out but restricted to 64 maps max.
Others here have already mentioned Graviteam and the stillborn Close Combat Campaigns.
[I'll pause here, because, years later, that project still deserves a minute's silence.]
It didn't need to be so complex. We just need some context for our tactical combat, as well as surprise - not knowing where, when or what enemy forces we will run into.
I heard of a bunch of guys who used TOAW III as the op map and CMX 1 for tactical combat. They reported excellent results but depended on a human umpire. He was that interface between games.
And yes, I agree with you, we shouldn't have to depend on human umpires.
The concept could be applied using TOAW III, TOAW IV, ATG, CM Mapping Mission or XConq as the op game and CMX 1, CMX 2, Graviteam, Steel Panthers and myriad other games for tactical combat. Alternatively, Graviteam could make their op map bigger. Armored Brigade might be about to deliver that.
Somebody above suggested that there might not be a market for this? However, we are looking at a crowded market. Sooner or later somebody is going to break ranks, to put some clear blue water between them and their competition, just to sell games. Why should that not be a grognard-friendly feature? Are grogs that poor?