eBay & PayPal can only recognise you through the following:
1. Your real name (but, as lots of different people share the same name, re-registering under your real name shouldn't cause a problem) ;
2. Your screen name. (Just choose a totally different name. e.g. if you used to be 'ShadyDealer' don't re-register as 'ShadyDealer2')
3. Your email address. (Simply get a new email account).
4. Your credit/debit card details. (Just use a different card).
5. Your IP address. (Most people have 'dynamic' IP addresses; simply disconnecting your router, and then reconnecting it, will change your IP address).
If you don't provide any of the same information that you previously did, there's absolutely no way that eBay could recognise you as a banned user.
The foregoing mainly applies to creating a completely new account but if you want to change the details on your existing joint account, simply be aware of points 1 to 5 above, so that you can ensure that the details you provide don't set any alarm bells ringing with eBay & PayPal.
Chris