An update (because I liked the idea of this thread, and because I'm rather pleased with my 'solution')
Use VBA to generate a graphical representation of a hierarchical data structure in Excel
came up with a solution to the above.
After much research and a considerable amount of hair pulling I discovered there is a known bug in office 2003 that prevents you from doing this (and of course, office 2003 is SOE around here...)
there is a workaround (do it in word, then paste/embed the result in a worksheet), but I was starting to lose heart by this time...
the end result was a rather negligible bit of code that produces a dynamic tree view of my hierarchies in HTML (WOOHOO!) - way simpler and far faster than my original approach
gotta love it when a solution comes from an unexpected quarter!!