I think I really need to work on getting my caching db_* API cleaned up and into the tree before too long ...
Berkeley School of Music uses it, too (and added some enhancements).
The OF folk use ns_sets extensively in dotLRN.
My code doesn't typically, in particular Greenpeace code, but I did implement db_multirow -cache and db_list -cache and I think db_list_of_lists -cache ...
I really like the idea of caching right in the db API ...