I think what your users are after is a very tall order. Acrobat Distiller can certainly combine files, add pages and so on - but I don't think it supports a programmed interface, so no chance of automating the Word and Access documents there. Distiller is also an expensive product, although very capable (it can do many other things, including turning PDF files into forms in which users can enter data).
Another product, the opensource PDFCreator, has a programmed interface - but I am not aware that the product can combine PDF files. Even if it can, learning how to program the interface is non-trivial.
I would recommend that the Word and Access reports remain ouput to separate PDF files. It would be possible to automate an e-mail message to send these files to a list of addressees, say - but as for combining them, the effort is not worth the return in my opinion.
-Stewart