Everyone is a little busy prepping 1.3, but you might make a go of it.
You could try adding a moderator group (Scan through the code and you'll see the admin mode sections.)
Another possibility would be to restore the CPG users table, then set up another coppermine installation that uses the same database without the BB integration. Turn the albums and user pics folders in the non BB install into symbolic links, shortcuts, or pipes (whatever they call it in each OS) to the folders in the BB install. This all speculation, but it might allow them to admin the coppermine gallery files and database without allowing access to the BB. Remove the config.php and the links to it in the new install, and they shouldn't be able to change the config settings. If you try this, do it with two test installs.
I expect a moderator group in the next few releases, but it sounds like you may not want to wait.