Let's say I print a part out of ABS and wait for it to cool. I could theoretically do this with several copies of the same printer, modified to use print beds of different compositions.
Will the material a bed is made out of affect how long it takes a part to cool?
Assuming you are meaning the build plate and not confusing it with a printed raft, yes, different materials for the build plate will have different cooling rates. I don't know the values of hand, but a Google search can get you to a formula to calculate how long a certain size build plate of a given material type should roughly take to cool. (I'm using the mobile app right now, so I'll have to get back to this answer later to give links and more details)