You might want to take a look at Calguns.net. The moderators there have been setting up group buys from various manufacturers for stripped lowers. Right now, there is a buy going on for Wilson Tactical lowers.
Not all lowers can be legally brought into the state. Essentially, there is a list composed by the Dept. of Justice that lists, specifically by manufacturer and model, the lowers that are banned from being brought into the state. For years the DOJ was working under the direction that all "AR series" weapons were banned (this way specific makes and models didn't have to be listed- if it was "AR" enough, it was banned). However, a recent court ruling overturned this thought, and reverted back to the DOJ having to specify exactly what makes and models were banned. The problem is that the DOJ hadn't updated their list since 2000, and many more manufacturers are fabricating the lowers. These manufacturers are not on the list currently, and as a result it is legal to bring them into the state. The belief is that the DOJ will add the new lowers to the list, thereby making it illegal to bring them into the state as well.
Until the lower is added to the list, you are required to have a fixed magazine. The Sporting Conversions unit seems to be preferred. However, if the lowers are added to the DOJ list, we will be required to register them with the DOJ. Once registerred as an assault weapon, the fixed-mag requirement will no longer be valid, and we can go back to having removable magazine AR's.
Sorry for being so long-winded. If you want a lower in Cali, now is the time to get it. There is no saying when the DOJ list will be updated (many expect it to be any day), so get one (or four
) while you can.