I agree with the idea of logging in to whm via a psk, however I dont know as I'd like to log in as root in that manner (too paranoid about my keys being stolen), some form of su method would be better in this instance imo in a similar fashion as ssh, you log in as a user with no rights other than being a member of wheel, then su to root.
e.g. you log-in to whm via a psk (as I hate the idea of an open password prompt - but you have to have it for resellers at present) and then type in an su password to get your rights, does anyone else agree, or is this a stupid idea?