Welcome U812...the more the merrier <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />. The yard keeper sheath in the store will NOT fit the Mud Puppy. I have the Mud Puppy and the small kydex sheath the yard sells.
There are a number of custom leather and kydex sheath makers here on the yard forum. I would suggest contacting one of them. Rainwalker has made me two for other knives and will be making the one for my Mud Puppy.
Here is a link to some work Rainwalker recently did for me:
http://www.scrapyardknives.com/ubbthread...ge=5#Post188078