Items with +spell haste

[Steamboat]

I am extremely interested in this stat. As far as I understand it, this would lower the cast time of your spells. That would be huge.

After poking around on a couple of databases, I could only find one item in game with +haste. I can't remember the exact name, but it was some sword "of wizardy." And it wasn't a flat +haste increase, it was a proc that increased the haste rating for 15 seconds. The sword was an epic world drop BoE, which sucks because I can't go farm a mob for it.

Do I understand the +haste stat correctly, and have you heard of any other items with the stat?

[Stigg]

At level 70, you'll need 15.8 points to gain a 1% reduction of cast time.

Mind quickening Gem - Increases haste by 330 for 20 seconds

Blade of Wizardry - MH sword +150 dmg, chance on spell damage to increase haste by 280 for 6 seconds

IF you can get enough without sacrficing other stats, I would say this is a HUGE output of damage, especially in boss fights.
Another one is Troll's berserking...I think between 158 to 474 haste (both melee and spell) for a little while.