Actually.... you can buy some right here in the U.S... though there isn't much left! 10g - $17 (not incl shipping)http://www.sugimotousa.com/mm5/merchant.mvc?Screen=PROD&Store_Code=SU&Product_Code=SHI1&Category_Code=SHI
Each year, Sugimoto USA carries a limited amount of temomicha (usually for pre-order, though they have a bit extra). I have tried it once, and it is very good.
However, if you want to buy this, and they are already out, feel free to ask me where else you can buy it. There is a vendor in Japan, Hiruma-en / Gokuchanin, who always sells it. It is sold in 3g packets, and the price is between $6, $9, $11, or $54, depending on whether you want "normal" temomicha
or the most expensive tea in Japan. (At least, according to him!) Others here at teachat have ordered from Hiruma before (including myself for the first time this year), so someone can point you in the right way...