Yo, Telltale guys!
You are selling pretty much all there is to have of Sam & Max except Hit the Road.
There is a very quick and easy way to remedy that. Using ScummVM as a wrapper will make any XP/Vista issues non-existent. The GoG shop is doing exactly this for other classic games.
Basically you just need an arrangement with ScummVM and Lucasarts. The technical details are trivial.
It seems to me this arrangement would be beneficial for everyone and you will become the all-time ultimate shop for everything Sam & Max :)