Full size and K size Special Weapons 10mm receivers on Gunbroker. I had to get one of the K size ones, as I very rarely see those. Seller said he had a couple of each. $950 each.
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=471083789
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=471436479