I take it you mean the Japanese end blown flute as played by Snake Davis? They're called shakuhachi and are quite easy to get hold of, although the higher quality ones cost a remarkable amount for a simple tube of wood. You can get them on US eBay. Try googling shakuhachi and you'll get more info than you can shake a stick at.
They come in a range of sizes and keys, but to truly be a shakuhachi they should be 1.8 feet long (that's what the word means).
Incidentally, shakuhachi is also Japanes slang for something quite rude:shocked:, which I shan't go into on a nice family forum like this.
Ive made one recently from a piece of 2cm dia. Bamboo. The trickiest part is making the mouth notch, which can make or break the flute. Also be very careful when drilling the finger holes as Bamboo can easily split. The fun begins once you try to master blowing the mouth notch, great fun !. I have a pdf. of the plans if anyone is interested.