Using directions I found on an Edmonton bike club site a few years ago, I made my own studded tires using sheet metal screws and a couple of old tires. They look pretty wicked. I used an old tube as a liner to protect the tube with the air from the screw heads. If you use a tube that contains the goo for sealing flats you have a pretty disgusting mess to clean up.
Since we have enough snow I thought I give 'em a spin. They worked pretty good. Got a great workout just going down to the store to get a gallon of milk--surprisingly more in the upper body than I expected. You're not getting anywhere quickly and you have to go easy on the front brake. The tires hold very well on ice and fresh snow, especially fresh snow on grass. The biggest challenge was loose, crushed snow. The front tire moved side to side from irregularly displaced snow. The back tire spun every once in a while. Overall, it was pretty manageable and very enjoyable. I hope to get a longer ride in tomorrow.