Not currently. I kinda wish you could - I mean, there's no effective difference between an unACLed mysql server, and a php app that everyone has that uses the exact same authentication. The problem would mainly be that it would be somewhere beyond a royal pain in the ass to do it differently, it would probably require recoding PHPMyAdmin to accept Session IDs from the Dreamhost Panel.
I love that piece of software though. There actually is sort of a way that you can disable it. If you install ruby on rails on every single one of your sites, you mod_rewrite rules will be so incredibly foobared that PHPMyAdmin won't work. Tech support will hate you for it though .
My presence here indicates that I have failed to find amusement in ingrown toenail removal.