You can't find a Bigsby locally. You have got to ship it in yourself. I bought mine from Elderly Instruments. I doubt you can find a Gibson P90 as well over here
I would recommend Lollar P90s. They are expensive but Jason Lollar is a very respected and experienced pickup winder and winds some of the best sounding pickups. I believe his P90s are very popular among players.
You can order them here in Singapore via Sound Alchemy Music.
If you aren't sure of the exact tones you want, can try Seymour Duncan, Tesla, and DiMarzio, these won't burn holes in your wallet.
If you're looking for boutique P-90s, try Suhr, Lollar or Fralins.