I'm also in the market for a 2012 CMS in socal.
2012 CMS inventory looks pretty high checking all of the socal MINI dealers. With 2013s hitting the lot later this month, I think dealers should be willing to deal on the 12s...
Nick Alexander MINI is advertising $1200 off all 2012 CMS and $1800 off all 2012 CMSA4. If they are openly advertising this, I'd think you could do much better there or elsewhere.
I haven't begun reaching out to dealers but if you can be patient, just keep monitoring 2012 inventory each week and if inventory remains high, the dealers will be under more pressure to move them off the lots. I would shoot for invoice or lower as the 2012 is now a year old and the price should reflect that. Much earlier this year you could pull $1000 - 1500 off at various socal dealers.
Let us know what kind of deal you end up getting. Thanks and good luck!