What about converting the Word, Excel, etc. documents to
Adobe
PDF format and displaying them this way? Using frames, this can work
pretty well (see the catalog at
http://www.mcmaster.com/)
A copy of the Adobe Acrobat Writer is not too steep in price
($250 for 5.0), and from my personal experience with version 4.0, works
very well. They also have a web site, http://192.150.14.203/,
which will allow you to make a couple of PDF files for free and try things
out.
I seem to remember some commercial plug-in that allowed you to display
excel files in-line; I'll have to take a look.