Within minutes of completing this video GOG.com sabotaged me by releasing the fourth game! So yeah, there is at least one place where you can buy it now! :)
This video showing up at the top of the Steam community content for this game. Very useful review. Never got around to playing these when they came out but on sale on humble bundle for a dollar in the tales of love and adventure bundle. Wish they would revive the Monkey Island series, means a lot to those old games who played the 90s originals.