Your best bet would be eBay. Over the past three years, I've seen two bottles of Oldest sold on eBay. I bought them both. Best of luck!
update Aug 5th
I've got a bottle for sale that I'm also going to post on ebay, but you can just it directly from me. I'm located in Singapore at the moment.
http://chicvoyagetravel.com/johnny-walkers-oldest-for-sale/
There are a number of places where one can purchase a bottle of Johnny Walker Blue. There are a variety of websites that offer this product for sale such as Master of Malt, Wine Chateau and 1-877 Spirits.
Johnnie Walker was created in 1865.
Johnnie Walker was born on March 30, 1945.
Johnnie Walker is 66 years old (birthdate: March 30, 1945).
Des Walker goes by Johnnie Walker Whisky.
nyse:DEO
Johnnie Walker whiskey made its start in Ireland. It was named after the man who first brewed it up and sold it out of a small grocery store. After his death, his sons took over the distribution of the now famous Johnnie Walker.
Johnnie walker
40%
keep walking
FUTURA
40%
The Keep Walking phrase was used in the Johnnie Walker advert. The meaning of the phrase is to keep on drinking Johnnie Walker as encouraged in the advert.