Hatsune Miku has been successfully miniaturised into a version superceding all previous in terms of sheer mini-moe, though perhaps even Mini Miku cannot compare to the nendoroid or even normal versions. The limited edition Mini Miku has been dubbed “Kocho Kore Hatsune Miku”, so expect it to become a collector’s item, perhaps.
Ultra-puchi Miku is set to be available exclusively at the summer Wonder Festival & Comiket, so you had better get your plane fare ready, or else be prepared to make liberal use of Yahoo Auctions. On the other hand, it seems quite possible hundreds of thousands of them will negate all rarity value.
In case you are wondering about the actual size, she is said to be some 20mm in height, or for non-metric types 1/16th of a shaku (6 bu). She is set to go on sale for a bank breaking ¥500.