There are few communities as awesome as the Civ modding community. They are one of the biggest reasons that the Civ franchise still exists today (awesome games notwithstanding).
I've tinkered around with doing something like this for SC2 replays, and it's actually a pretty difficult proposition.
SC2 replay files only store the low-level commands issued by the player: selecting and deselecting units, movement and attack commands, build commands, the like. It doesn't contain any information about resources or units produced, since that's handled by the game engine.
In order to figure out what actually happened in a given replay, you've got to either re-implement the SC2 game engine, or code-inject the SC2 executable to grab the information you want while it's playing the replay file.
Since the first task is monumental, and I have no experience with code injection, I shelved the idea until there's something like the Chaos Launcher[1] for SC2.
I didn't add anything to what's already out there (I don't exactly have the patience for reverse-engineering). The most comprehensive overview of the replay format is the wiki[1] for Lauri Virkamaki's phpsc2replay project. Head and shoulders above everything else I found, which were mainly random forum threads.
The original StarCraft would almost be too easy: if you look at the system requirements, it's clear that the whole game could be ported to javascript and still run smoothly on modern systems.
