I run multiple orgs and am centralized support in one org for the users of all the other orgs. Rather than burden them with signing into the Self-Service Portal to view their Cases, I'm considering how best to link them to it seamelessly after they have already signed into their home org. SSO is out, we have no network. oAuth might work if the SSP could sign them in using their User credentials, however I'm most inclined to pass their credentials via POST from within Salesforce.

Any better ideas? Any stringent objections?