Hmm, the website was updated:
http://hirokikikuta.com/cd/tiara-2011.html
The album is now listed in "Now Available CD" and there is a amazon.co.jp link:
http://www.amazon.co.jp/gp/switch-la...language=en_JP
Says "Temporarily out of stock" for me, but has a release date of 2011/4/1. Going to keep an eye of this one...