How about this:
http://www.amazon.com/Quantum-ES2-Du.../dp/B0000C5RR8

http://www.bhphotovideo.com/c/produc...rgy_Saver.html

These would obviously do what the OP wanted -- though the price is not
right. One might solder lengths of copper tubing (which you can get at hobby
stores) to metal disks -- but I don't know how sturdy they'd be.

WARNING! The following is off-topic -- but worth thinking about.

These dummy cells are supposed to be energy savers, because they let you use
only three AA alkaline cells in a four-cell flash. This works, because most
flashes operate correctly with nicad or NiMH cells, which are nominally
1.25V (rather than the 1.5V of alkalines).

However, this is a great way to waste money -- and not just the cost of the
dummy cell. With only three cells in the flash, you won't be able to
discharge them to as low a voltage as you would with four. That means you'll
have to discard them sooner, and you'll get less total energy out of them.