Another favorite is Recon. Not as crunchy as T2K. But bit more than some games. Its scope is a little bit limited, skill wise. You can definitely tell its based off an old miniatures game. But its still a great little game.
I've thought about "OSRing" both of these. Even done a little ground work on it. But T2K is such a large thing, for lack of better words. That it is very intimidating. Then Recon which I think is ripe for an OSR treatment. But then really it would only be for personal consumption. As Kevin Siembieda is a pretty litigious guy. He writes and produces some really cool stuff, but man major control freak.
But I think a military RPG is a missing niche in the OSRish world. I mean there are some great spy games, which is a good step in the right direction. But no straight mercenary, special operator game.
I'm really digging "The Black Hack" right now. But I'm not sure its a good fit for it. I'm not sure about gun combat. I think the rules are great for ancient melee/ranged. But I'm not sold on modern yet. I would like to see how they work it in "The Front". At the same time I don't want to seem like I'm ripping it off, or not being original on my own.
Another thing I ponder about is skills. While again in The Black Hack using attributes works for it. I could even see it working for a pulp/1930s game. But I'm not sure if it totally fits with a modern military game. I think it would work better with some sort of skills or bonus to skill type actions.
Anyways just some random thoughts. So some ideas I'm rolling around.