Last year I bought a reproduction hand crank from Jim Erickson, for my GPW.
One of the best moves I ever made. This year at the beach (Aug, 2000), I was glad to have it along. The last day there, the old battery died. But the trusty hand crank got it cranked right up.
Good thing I'd have the foresight to get it, and install a military crankshaft nut on the CJ L-head to mate up to it. Like I said, I've had this a year, it's been riding and bouncing around in two different jeeps, been to the beach twice, and still looks like the day I got it. (Except for the grease, and wear marks from the hole in the bumper). I never painted it, and there's not a lick of rust on it.
I'm not sure what kind of primer Jim used on it, but it's sure something else. 
Quality wise, it's gotta be the best I've seen. I've seen others out there, but I remember when I bought this one, it was $10 less than the website I saw another on.

Jim also has a repro CJ2 folding crank, and I believe he's making an M38A1 battery cover now also.
You can contact him at  jephoto@brainerd.net . Or watch for his auctions on ebay.
From experience, he's a real square dealer, and and I'd recommend him.
I've bought many items from him, and would not hesitate to do so again.

 

Here's a couple shots of the MB/GPW hand crank.
handcrank.jpg (90032 bytes) handcrank_end.jpg (10087 bytes)