GSC has just posted an apology and correction regarding pre-order date for Nendoroid Hatsune Miku: Mikumix version posted in the latest issue of Shueisha’s Weekly Young Jump magazine, which was published yesterday.
Apparently there is a typo there mentioning that Nendoroid Mikumix will be available for pre-order starting October 25, 2011, whereas the correct one is November 25, 2011. Yep, it seems the reservation for this eccentric Miku will be available on Friday, next week. It is still unclear whether she will be a limited, exclusive, or normal run. ^^
Note: The actual English name for this version of Nendoroid Hatsune Miku is still unknown. It reads “Shūkan hajimete no Hatsune Miku” in Japanese, that literally translates into “Hatsune Miku: First Weekly version“. However, I think that the term “Mikumix” is more frequently used to describe this version of Miku, hence it is used in the posts.