Did I say the coding would be modest? Doh!
I've implemented the Guest permissions re-work on our dev server at Sloan and tested for correct function on the forums "one message" page. This, recall, is where we found the bug that exposed the larger problem with Guest status.
I have the following items left:
a) fix the view/add/edit user pages to query the new Guest handling mechanism instead of the old one.
b) test the other places that check for read_private_data
c) test against postgres (already converted most of the SQL)
d) add message keys in a few places
