Space Hulk?
Sorry, I'll get my coat.
Actually, it isn't a joke, now I come to think of it. What you're describing is exactly what Space Hulk is. But whether you want to shell out for a limited release Games Workshop product rather than try to find free downloadable rules and using your own minis, I don't know. If you're looking for a 'game in a box' and you can find one on ebay, then it sounds like Space Hulk would fit the bill perfectly.