set one pc up like you want them all to be set up, then sysprep it using the generlize option (this makes it hardware independant) . (also win 7 can only be syspreped 3 times unlike vista xp ect.)
Ghost the image or use a third party imaging software.
load the image on the new pc's
i have found that with oem installs like lenovo and dell when you reload the image has problems (bsod), but the work around is to download an oem verision of win7 from technet and use that one.
as for pulling keys, i dont feel comfortable sharing that info, not sure if it violates tom's tos, but you can google it and find a few options i am sure.
here is a video on how to sysprep Click here
load tha image on the pc.