Griswold's Redemption Caduceus should do 4fpa Fury if you socket 3x 40/15ias jewels.
Base speed: -10, and 40% ias. with 3x ed/ias,
it will have 95% WIAS.

The Zerker is nice.
Berserker Axe:
24-71 Dmg
Range 3
Base speed 0

You'll need 95% WIAS, which can be achieved by 4x 40/15ias + 2x Shael (100% IAS) for 5fpa Fury.
A superior 15% Zerker after socketing will do:
(4x 40)+15 = 175% ED
(min+1)x(1+1.75) = 68
(max+1)x(1+1.75) = 198
68 - 198 Dmg, 133 avg.

What's my thought on the axe...?
Well if you have one, you will make me jealous