Based on Paul's comments in the thread on polestun, the Spear is the ideal stunlock weapon, as it's the fastest non-knockdown pole with a raw swing damage >15.
Also, he indicated that all non-knockdown poles with raw dmg >15 have the same 50% chance for 0.8s-1s stun. Maybe high dmg thrusts and overheads push that number closer to 1s, or maybe it's random, but either way, I think my suggested 6/33 Spearlock build would be good for some laughs.