Discount Pentax eyepieces, like xw10 on
amazon.co.jp :
http://www.amazon.co.jp/s/ref=nb_sb_...ds=pentax+xw10
$325ish AU including shipping.
Your existing Amazon account wont work unles you have a Japanese Amazon account.
Sign up, put your address as an international address and you can order from Japan.
There's lots of different discount stuff on there if you are after Japanese made stuff!