T-Rex makes them. Here's the link....

http://www.t-rexproducts.com/Dynamic/default.htm (click on the left on Reptile Products then follow the 2nd link "T-Rex Frozen Reptile Nutrition Series", linke for "Snake Steak Sausage" is there...sorry I couldn't get it to link directly)

Pretty interesting the bit about how handy they are to powerfeed (blech). When I clicked in the ingredient list it said...

"Ingredients:
Meat & Meat Derivatives"

Oh well there's a complete list for you. Sorry I think they are a bad idea and personally wouldn't ever consider using something processed like that for our snakes. They happily get the rats I raise for them to eat. I know what went into those thanks.