I'm quite sure almost any game(including FF:T) that uses magic uses this, except, they usually don't set it up that you have to be extra-carefull with your mana.
When running out of mana, mana-abilities(spells) become unavailable and characters have to use less effective attacks/actions.(hitting the opponent with your wand while not wearing any armor)

Okay, that makes sense. For some reason, I was thinking that you were saying that, in most games, mana was necessary for any action, including movement and things like that.

There are a few games out there that use fuel(and usually ammunition as well) as a resource, and include some kind of supply-unit(s).

I think an action point system works well. Especially if you allow enough action points to accomplish more than one phase.

For example I will use an artillery unit.

Artillery: 10 ap

Move: 5 ap

Set up: 5 ap

Attack:5 ap

Pack up: 5 ap

That way you have more combinations than just being able to perform one action per turn.