I think the PIM that would have - or might have - met Chris' requirement
reasonably well isn't available any more. It was the old Claris Organiser
for OS9 and earlier. Years ago now.
You had a calendar with appointments, notes, contacts, one or two other
things. Then any one element of these could be linked to any others in some
simple way. So you had a sort of ad hoc grouping of (say) a person's contact
details, every appointment you had with them, every note of every phone
conversation, and maybe the text of all correspondence. You got to each
element of the set by clidking a link. And you could have as many of these
bundles as you wanted. In addition there were the usual categories.
So Chris could have had journal entries associated with agenda items, or
anything else. Snippets of code associated with a project. Reading lists
from people at a given class. Anything at all could be made into a set and
once you hit one, the others became available, but if you also wanted to look
at items by category, you could do that too.
Later on it was sold to Palm and marketed in two forms, the Windows form of
Palm organiser not having any of this linking functionality, but the Mac
version kept on with it.
It was amazing. I kept looking for something like this too, and hoped maybe
Chandler might turn into it, but alas... It may have been a functionality
that was too obscure for most people to bother with, but once you got used to
it, it was very powerful.
Al