<< If the 940 socket offer more stuff is OK.
A SledgeHammer CPU will use all the pin , a ClawHammes will leave some pin unused.
Just think about a mainboard with two groups of DDR , if you use a Claw you have to fill only one group , with the Sledge you must fill the two groups.
Is like adapting a Slot1 CPU on a Slot2 mainboar >>
I doubt it because that is hardly cost effective (ClawHammer boards will need to have the traces for Dual Channel DDR), and besides, like AA0 said, SledgeHammer is aimed at an entirely different market and while it may be possible in what you are saying, AMD would never do it.