Gathering data for a page in a structure which mirrors the page layout can make it more awkward to share.
Okay, this point is valid but it is sumountable. The last peice of script that I posted in this thread would allow common data to be shared between any number of composites or page fragments.

Now, this leads to this problem... What or how do you determine if one composite or another one for that matter, isn't interested in knowing that common data? For example, as you've pointed out, the HEAD would need to know about a title, but not so the FOOTER.

Please continue McGruff, as you are going somewhere with this