Ok, I know you're not supposed to have multiple ebay accounts, but many of us do, and a little problem has always been keeping logged in to more than one account on the same pc. AS soon as you log into an account, you cannot log into another until the first is logged out.
So, I've been doing a bit of thinking and found that you CAN log in to multiple accounts by opening multiple PRIVATE (Firefox, IE, etc) or INCOGNITO (Chrome) browser windows. This has saved me a lot of logging in and out time.