GSC has officially confirmed that Berserker will be joining Saber Alter, Archer, Lancer, and Caster in the Nendoroid Petit Fate/Stay Night Extension Set. Yes, that would make him the largest Petit ever – and we mistook him for being a regular-sized Nendoroid due to his size. In any case, this set will be released on October 2011 with a price tag of 4800 Yen.
Meanwhile, a staff of GSC has posted a pic of the container for Nendoroid Gumako: Support version. Nothing special there, except for the stand base that being placed on the bottom-right corner instead of the usual bottom-center placement. ^^
(Thanks for the news tip, Clerericus! ^^)