[Zope] faster navigation with sorted content-list-property?

Dear List, the NFGnav-product and most navigator solutions that I know (including my own ones) loop over the content of folders on every page-hit. If there are several additional dynamic navigation-elements like dropdown-lists, breadcrumb-navigators etc. there is a lot of timeconsuming looping for every page-hit. With a sorting-feature it will be even worse. Wouldn´t it be better i.e. faster to store the sorted-content of the folder in a list-property that changes whenever a document or folder is added to that special nav-folder so that different nav-methods can collect the same static content-info? May be someone uses this kind of nav-folder already? Does anybody have some comments or hints about that? Thanks a lot, Elena