The only Pak Mei I know about in So Cal is Eddie Chong. Mixed Wing Chun and Futshan Pak Mei - see him on YouTube. His style isn't mainstream, but he's been around awhile, you might find it interesting, but I don't know how far he could take you. Then again, most students never get past the basics anyhow.
San Fran has another Futsan Pak Mei Sifu, Zhong Luo, mixed Pak Mei and a bit of MMA, likes to make movies too. A little more mainstream, there's a bit of him on YouTube too.
In a match, I'd put my money on Zhong Luo over Eddie Chong.
There may be others, Pak Mei has a tradition of keeping private and small intimate families, the two above are notable for their self promotion.
Whatever you do, don't get involved with that "White Tiger" BS that tries to pass itself off as a secret branch of Pak Mei. Doo Wai is a crazy old man, and his organisation is mostly internet warriors who are busy fighting it out between themselves. There isn't any real kung fu amongst them, just lots of cons and made up dross to separate you from your hard earned $$$.
If you also look into SPM (any branch of southern praying mantis) or Loong Ying (Dragon Style) you may find the kind of juice you're looking for.
Guangzhou Pak Mei Kung Fu School, Sydney Australia,
Sifu Leung, Yuk Seng
Established 1989, Glebe Australia