My friend has a very large metal hand crank grinder we use when we gang butcher. We do as many as eight hogs at a time and once did ten deer in a day. It goes fast when one group butchers, one group wraps, and one grinds, etc.
He built a table with a lower shelf. He used sheet metal on the top so the meat could go right onto the table top. He mounted the grinder near the edge of the table, and then built a jack shaft that runs off the handle mount bolt, down to an electric grinder. The jack shaft of course slows the grinder down from the motor.
If I had large amounts to do, I would have an electric grinder. I have a hand grinder and did as many as three deer with it. It was a chore and my arm was sore for days after ward.
http://www.sausagemaker.com/ check out this place for a grinder. They are a little high, but good quality. Also their vension kits are excellent..
Another place to check for grinders is Harbor Freight...
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=46749