They are sold at http://eng.yamato-toys.com/items/result.php?word=%81yGANTZ%81z and elsewhere. Should be a list of everything out there somewhere to add to this page. Dream Focus 19:55, September 17, 2009 (UTC)
http://www.mbok.jp/_l?_CODE=%82%A0&_SRC=head_sr&r=fc&gq=1&q=Gantz&c=&imageField.x=0&imageField.y=0 shows on two pages the various ones. Several for both Reika and Kishimoto, different outfits, and apparently a male character as well. Dream Focus 15:49, December 5, 2009 (UTC)
Amazon.com shows 6 Gantz Gashapon, and two other figures. Dream Focus 15:53, December 5, 2009 (UTC)