With Patch 1.4 well and truly live (full patch notes here), I had missed the detail on whether SWTOR players on the three oceanic servers had received the 12th character slot. The question was asked on the official SWTOR forums, and Joveth Gonzalez answered in the affirmative:
Yes! Oceanic servers now have 12 character slots with the latest update
Having a whole 4 toons on local servers, this is far from an issue for me, but it’ll be a bonus for some. We’d love to hear from you if you have 12 characters and how this has helped you – jump in!