Arms of Plenty (level 3 sorc/wiz, TOUCH RANGE) Lords of Madness page 209.
Give the target 2 additional arms that can make attacks, as well as a rend. A few things of note:
"Since the claws are primary attacks, you can attack with them in addition to making your weapon attacks without penalty."
Unfortunately though:
"The claws cannot be used to wield weapons or manipulate objects."
2 additional attacks at 1d6+str, then a rend for 2d6+1.5*str. Not bad for a buff to stick on your BFS at lowish levels.