Devel::SizeMe is a variant of Devel::Size that can stream out detailed information about the size of individual data-structures and the links between them.
It can do this for the entire perl interpreter internals as well as your own perl data structures.
It comes with scripts for storing this data in a database and visualizing it in various forms, including graphs and an interactive treemap.
Current implementation is alpha and somewhat hackish in places.
It currently doesn't work on systems built with -Duse64bitint (use -Duse64bitall if possible). Patches welcome - I think it mainly needs %d's etc changing to use IVdf etc.