Hi Dave,
Ain't much to it. All you need is a piece of angle and something to stick it to. I got this piece of wood molding from the odds and ends bucket at the local Home Depot. A piece of 1x3 to make the base and a couple of shorter pieces of angle to hold it up. Lots of wood glue to stick it all together.
Then you just use a strip of masking or duct tape to hold the pack down while you solder. You would have one loose cell in front of the semi-finished pack. Solder, smush them together, lift the tape, do another.
Ghetto? Sure. But I can do everything from AA's to D cells with efficiency and accuracy. Of course technique is key, but the jig is simple, cheap and works great.
Wilkey