Character concept and build advice

[Scott Wilhelm]

There are the Alchemal discovories Vestigial Arm and Tentacle, but these don't give you extra attacks.

There is the Psionic Class Aegis, at level 5, you can grow 2 more arms which you can use in combat.

There are creatures you can polymorph into with multiple limbs.

There are magical, supernatural, and technological limbs you can graft onto yourself.

[Detoxifier]

This might be of some help.

http://www.d20pfsrd.com/gamemastering/other-rules/variant-rules-3rd-party/4 -winds-fantasy-gaming/The-Loss-of-a-Body-Part/Prosthetics