You may find a new version of the checkuser access policy here
http://meta.wikimedia.org/wiki/Talk:CheckUser_Policy#Access_.28new_version.2...
the main differences are * it takes into account the fact some local communities with arbcom do not necessarily want to delegate appointement of checkusers to their arbcom * any local project may choose at least 2 people amongst the already approved checkusers, with localized requirement (the local community choose itself percentage of support, minimum number of votes etc...)
Which would allow to make Essjay and Karynn checkuser on en.wikibooks if the en.wikibooks is happy with this.
Warning : the idea is not that all checkusers be selected by wikipedias and later imposed on other projects. The idea is rather that generally, a person widely supported in one project to do a job... is some one we generally trust to do the job properly anywhere.
So, if wikicommons wants to appoints 5 checkusers from 5 different languages, all those 5 may serve on various other projects. The one requirement to keep though : always at least 2 checkusers per project.
Opinion ? Please comment on the meta page. Trolls not welcome. I do not have the time this week :-)
ant