My friend that knows the answer to such q's is away on holiday and won't be back till next week but I can ask him. Until then, the folowing informtion is based only on conjecture, and as I am a firm believer in the merits of CRT TVs I know little about high def standards. However:
Whether it can output 720p would depend on whether it has HDMI out, right? If so, could you not just check on the mac website and/or in an instruction manual? If it doesn't have this option then I would suggest not.
Like I said though, I could be wrong.