Google announced on Google+ that you can soon login to multiple AdWords account via the top right menu. It basically will let you toggle from one account to the next very quickly.
Google wrote:
Today, we’re introducing a new, simplified workflow that allows you to toggle between multiple Google accounts without having to log out and back in again. With this update, you can now:+Manage multiple AdWords accounts simultaneously in the same browser
+Stay logged into multiple AdWords accounts or other Google accounts at the same time
+Save time switching between accounts with different logins
Here is a screen shot showing where you click to access the accounts:
To use the multiple account sign in for your AdWords accounts, you can click on your Customer ID or login email within AdWords to open the account selector. Then select to add more accounts using the "Add Account" button.
Forum discussion at Google+.
