Extended notes about a transaction

[Gregory Novak]

It's becoming clear to me that I'd like a way to associate extended
information to a transaction in Gnucash.  This could be as simple as a
little icon on each ledger line that, when clicked, brings up a little
text field where one can type a bit of information.  Hit "ok", and
then the next time you click the icon you'll see what you previously
typed.  It's also easy to see how this could be used to attach
extended information to specific accounts, or to the whole set of
accounts.  

Info attached to transactions could be used to notate things like "Joe
owed me $30 and I owed him $20, so this $10 settles our debt."  Info
attached to accounts could be used for things like: "When the big
deposit clears, remember to transfer part of it to some other
account."  And info attached to the entire tree of accounts could be
for things like "In June, I spent too much on widgets.  Make sure that
doesn't happen in July."

It seems likely that someone has already thought of this, but perusing
the menus didn't reveal anything to serve this purpose.  So that's the
question: does this already exist?  If not... would someone care to
point me in the right direction as far as implementing it?  (no
promises, but if it's not too hard I might be willing.)

Thanks,
Greg