I have FM12 on DVD on my current laptop, which is on it's way to laptop heaven. I am looking at the ultrabooks that are currently out (HP to be specific), but it does not have a DVD player. Not wanting to buy an external device, how can I transfer the game from one machine to the other?
You don't transfer a game installation between two pc's. You install them the game on each pc. If the ultrabook doesn't come with a dvd drive you can buy en external dvd drive an plug it to the usb stick. Or you can do it the cheap way and install it through steam. As you have already installed it once, you have connected the game with steam and as such you don't need the FM dvd disc any more.
So, against all hope there is no way to be able to d/l via Steam, using my authenticity code?
Not sure what you mean, you've already authenticated with Steam so you don't need the disk or the number again.
Just install steam on your new PC and log into your steam account, FM will be waiting there in your library for you to download.