I've already mocked this up for Traveller, and I can say it plays really well with that rule set. I'd love to see an official treatment.
The way I handled heat sinks was to treat them as having either 1/4 the ammo (with a DM of -1 for each increment of 5), with the player needing to wait a full round to cool down (and reduce the DM to 0), or 1/2 the ammo and they need to worry about carrying extra heat sinks. I give my players the option of either. Since combat is short and they dislike clutter, they tend toward cooldown over heat sinks.