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You have to use a hack to do it. This is an idiotic question, simply because of that fact.

I'm not sure why you consider plugging in a usb mouse and clicking the button a hack. Running in clamshell mode is not difficult at all.

As for the screen, the unibodies should better off because of the glass on the glossy display, though I'm not sure.
 
Just make sure that it is well ventilated and I would suggest installing smcfancontrol and upping the minimum fan speed while running in clamshell mode, just to be safe. If it gets too hot the screen could be damaged as a result of it being exposed to too much heat. You can use caffeine or InsomniaX to prevent your laptop from sleeping when you close the lid.
 
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