If you have access to a lathe, its actually really really easy to make your own.
Check out the pics from my Project thread:
http://board.marlincrawler.com/index.php?topic=4401.msg46079#msg46079I just made matching 1" spacers and then ran down to orchard and got some (stupid american) bolts with a 9/16" head so I can still use my 14mm wrench.
BigMike