I personally think that a central pool (how central? Should it be common to all languages of Wikipedia, almost like the Wikimedia Commons?) is a subproject too big to be implemented inside Wikipedia. For example, in some cases this pool needs to link to works digitized in Wikisource or in external digitization projects. And at least Wikiquote and Wikinews should benefit from using the same "central pool" as Wikipedia. And if "Wikicat" is set up as a new, separate project, the people who should be involved there are already considering the global need (inside and outside of Wikimedia Foundation projects) for new bibliographic resources. My current guess is that the demo.openlibrary.org, which runs under the Open Content Alliance and/or Internet Archive, would be the best place for this.
Wikimedia's answer to Google Scholar? Sounds good. I imagine we could get quite a lot of websites to use it for all their citations.