Back in my college days, one of the major campaign systems we played was something called
Starfire, a space-combat game (based on the "
space is a 2D ocean with surface naval ships" trope) which was fairly unique in being a strategy game with a
referee. That is, in addition to the players, there would be one designated "spacemaster" who would run various "non-player races" and allow for double-blind encounters between players with limited intelligence gathering. In effect, it was an RPG, but using starship navies instead of characters. The campaign game ("Imperial Starfire") was written by sci-fi author
David Weber, who also contributed an elaborate historical universe (RPG players might call it a "campaign setting") that functioned as a model for writing up the history of your own civilization.
There really aren't many other examples of games that follow that pattern, despite the fact that this was almost certainly the original play style of the Lake Geneva
"living fantasy" campaigns that gave birth to modern role-playing. The combat rules were borrowed from miniatures (Chainmail), and it was understood that players would build their own castles and acquire little fiefdoms full of soldiers and mercenaries. So there's a certain logic to creating a "fantasy Starfire" game, a strategy-RPG hybrid that can scratch the itch of players who want to run armies instead of just heroes. I'm not aware of any other strategy wargames but Starfire that use a referee/gamemaster, but if anyone knows of any, I'd be interested in hearing about them!

At the moment, I've been following the fundraising drive for something called
Domains at War, which looks like it might fit the bill. It's written in such a way that it looks primarily oriented toward the cooperative style of play popular with RPG groups, but I think the economic balancing is tight enough that it could be easily adapted for a competitive game between players running rival kingdoms or alliances. The rules are extremely extensive, allowing resolution at three levels (strategic/abstract, 120:1 miniatures, and man-to-man), with the promise of consistency between the outcomes of all three levels of combat resolution. This all looks very appealing, especially since the abstracted combat allows for the quick resolution of mismatched battles without much uncertainty in their outcome. (Being forced to fight a doomed battle was always a chore in Starfire!)
I'll be reading through the rules over the next few weeks, to see how well they might work for creating a fantasy campaign on the strategic level, with players controlling territory and sending armies against one another (or against the non-player races of a referee).