CTAN has a new package: coollist
manipulation of lists
See this package at http://tug.ctan.org/tex-archive/macros/latex/contrib/coollist . You may get a better network connection by using a CTAN mirror near to you; see http://tug.ctan.org/tex-archive/README.mirrors . Our service is supported by the TeX Users Group http://www.tug.org . Please join a users group; see http://www.tug.org/usergroups.html .
coollist – Manipulate COntent Oriented LaTeX Lists
Lists are defined as a sequence of tokens separated by a comma. The coollist package allows the user to access certain elements of the list while neglecting others—essentially turning lists into a sort of array. List elements are accessed by specifying the position of the object within the list (the index of the item).