Replace access denied on user/register for logged-in users with a redirect

Best resource on this that I've found:

logged-in user + /user/register -> access denied
http://drupal.org/node/118498

There's no reason for this-- even user #1 gets access denied here, and users who could go to admin/user/user/create -- access denied might be technically correct, you can't re-register, but it's nonsensical and annoying.

This needs to be a core fix or at least a module. Giving logged in users access denied on the registration page is just silly. We the Drupal using community need redirect options, or at least redirection to the user's profile page (but preferably an option to do the home page or something else).

My particular use case is I've set up a workflow (or a redirect in login toboggan) to immediately take instantly logged-in users (a logintoboggan option) to

Anyone who follows that link twice gets denied.

The best solution is the workflow registration I really want-- let people post content or comments and log in or register at the same time.

A comprehensive solution for this (not losing data if switching between logging in or registering, or a couple failed attemps), Agaric will give money to get done or do for money.

Resolution