I know that the longs drugs on Pleasant Valley Rd. in Oakland (formerly Payless) has the Kaffir lemon (or is it a lime?) on a dwarf rootstock, as well as many other citrus trees. Their garden center has been there for at least 40 years and is surprisingly good.

I have purchased lemongrass from a seller on ebay, but I have read frequently of people buying it at their local Asian market and planting it with excellent results. I think you could have the same results with the Galangal or any type of root.

OSH usually has a couple Kaffir Limes tucked in among their other citrus trees in 5 gal cans. You can spot them easily by the double-lobed leaves. I used the leaves and sometimes the zest from the tiny limes. Here in Sunnyvale I grew lemongrass in a 5 gal can, and although it multiplied like a weed, it never had as much useable stalk as the 15" or so ones you can find at asian stores. Bugs got to my holy basil, so now I mostly stick to Thai chilies which do extremely well here.

-Babka

If any of your local nurseries buy from Monterey Bay Nurseries, they can order galangal for you. lemon grass shouldn't be that hard to find, it's fairly common. Kaffir limes are usually available or can be ordered

Yeah, I've wondered about growing galangal as well and if the fresh root at local thai markets could just be potted directly. I know it will grow in SF climate - it apparently likes the same conditions as ginger root.

I have had trouble starting grocery market galangal although others have been successful. It can be grown in containers but really needs to be in the ground to do well. When in containers a long pot is good because it sends out growth laterally.
Lemon grass can also be grown in containers but thrives in the ground.
Have you tried connecting with local Thai gardeners? They will often have varieties not found in stores. Another source is swap meets.
You should have a ton of Thai stores in your area. Look for things like mints, tubers, basils, & mustards. They can oftentimes be propagated from grocery store stock. Some small stores will also sell small plants not available elsewhere.

Richters of Canada has some seeds and plants of Thai herbs such as rau om, Thai basil, lemon grass, and others. Not to mention other unique items.

as far as lemon grass goes, I've read it rated at Z11 but I live in CA9b and it survives our winters, dies back but resprouts. I have seen it at HD and Lws in their herb selections.

enjoy,
-Ethan