Taking into account some suggestions and comments, I made some changes to my previous attempt at redistricting California. I conceded an additional 2 seats to the GOP, which concomitantly makes a number of other seats more strongly Democratic. The additional 2 safe GOP seats are CA-4 and CA-48. Here's what version 2 looks like, overall:
I decided to try my hand at redistricting California's Congressional districts for 2010-2012, using Dave's Redistricting App. After playing around with it a bit, here's what the map I came up with looks like overall:
Here's the 2008 Obama/McCain vote in California, on the precinct level:
