eMac spanning hack question (single screen mode possible?)

I have the latest eMac 1.25ghz, and seen the spanning hack. I have to agree with some postings here on MR that splitting the VRAM to 16mb for each screen slows down screen performance a bit (tried spanning on my PB 12" rev. B).

Is it possible to run the eMac in a type of "clamshell" mode? Meaning that only one screen is running at a time, outputting to the external only?

 

Sorry for the bump, wanted to see if anyone had experience on this before I make the trek out for the VGA adapter.