If you want to do this purely using SRD and linkable material, there's really not that much anyone can do to help you.
But here's my best shot:
Here's a
list of things that grant Rage like abilities.
Here's a
list of classes available online.
Here's a
list of ways to get natural attacks.
Here's the
Whisper Gnome.
The
Kobold variant is also good, especially if you focus on natural attacks. At early levels, it grants you tremendous advantage. And using the Greater Draconic Rite of Passage, you can get +1 to your Sorcerer caster level (including spells) in exchange for 2 feats.
I would suggest using an over-powered template, such as
Mineral Warrior,
Mulhorandi Divine Minion, or
Entomanothrope. Normally responsible DMs ban these, but a Barbarian/Sorcerer is weak, and without supplements they're totally nerfed. So maybe one of these would help a lot.
Can you use crystalkeep? If so, that opens up a lot of doors for you.