If hes got a old 15" lying around then tell him to get it on there! 🙂
It will make this easier since he wouldnt need to swap the cables unles he HAS to play the particular game which he wants glide for, on the big monitor...if he has to play in glide on the main monitor, then hes gonna be switching cables im afraid, whether it be manually or via some sort of switch.
He will like it, its great for both work and play - cant beat having all this real estate, whether it be IE, photoshop, working on multiplae documents simultaneously, or watching movies while you 'work' (IE again 🙂 ) 😛
LXi, you can enable/disable multimonitor support in a single click if you got the right stuff on (if not, take a wee trip to display properties, probably about 5 clicks normally, hehe)....you can change the primary monitor equally as easily, so enabling/disabling vid cards isnt a problem...though as we all realise, if he wants glide on the main screen, that means a vodoo powering it, and a consequent swapping of cables... 🙂