Elthos RPG is a light weight RPG mini-system that has tactical combat rules. I created a map and pieces in Roll20 to test the Quick & Dirty Combat Rules for my RPG (in the process of being readied for publication). It takes about 10 minutes to learn the rules and each game takes probably about 20 minutes to play. There are a lot of options in terms of how to configure the game, but at the moment I am playing a Capture the Flag on wilderness terrain with two balanced teams. We each play one team. More sophisticated versions are feasible as well. If you're interested let me know. Thanks.