What about this?
www.vbd.com/noc/shop/products_detail.asp?CategoryID=49&ProductID=322You could buy a AR reciever from someone out of state and send them this kit, they install it and the lower goes to you local FFL dealer and you get a fixed 10-Round AR.
What I'm curious to know is if the "tool" portion of the law has been tested. I mean it CLEARLY says that a tool is required...I don't see ANYTHING in there about the magazine needing to be riveted, welded, glued, etc...
# Penal Code section 12276.1:
# (a) "detachable magazine" means any ammunition feeding device that can be removed readily from the firearm with neither disassembly of the firearm action nor use of a tool being required. A bullet or ammunition cartridge is considered a tool. Ammunition feeding device includes any belted or linked ammunition, but does not include clips, en bloc clips, or stripper clips that load cartridges into the magazine.