I have a date, and I want a feather boa. But it doesn’t occur to me offhand where you go to get one.
There’s a shop near me that sells materials to make dance costumes. They have exquisite boas for a price. Unfortunately it’s a bit far for you to travel but you could try a dance supply shop.
I used to see them at fabric stores.
They have a bunch of boas here http://www.ostrichesonline.com/cgi-bin/store/shop?cmd=boa-index&?source=overture
or you can try a google search on “feather boas” I got mine at a local costume shop.
Try Frederick’s of Hollywood, if there’s one near you. According to their web site they have 40 stores in CA.
If none are close enough and you don’t have enough time to order online, try whatever local sleaze shops are available in your area, especially if they cater to gay/lesbian interests. For example, we have a place in DC called The Pleasure Place that sells naughty nighties, etc.
If you have no such shops of any kind in your area, move to some place more exciting 
Dance stores, costume shops, novelty shops, thrift stores, michael’s (craft store) used to carry them… in fact, if you can’t find a feather boa near Mountain View, you’re not trying.
We have Halloween Stores that open in August in our Malls and close in October (when their space is typically taken over by the X-mas stores). Anyway ours opened this week, Boas of every color are there (was there just yesterday) In fact a man made the store groan with his observation of the many colors :
“Rainboas”
And don’t forget Ebay 87 there at the last count.
I think I’ve also seen them from time to time at those teenage accessory stores like Afterthoughts or Claires at the mall.