Here's a few ideas:
ItemSet 293842
*Iaso Cuffs augmented with Haste+4%
Lowest recast: I would use something like this if I was stunning as soon as the recast is up and accuracy isn't an issue.
ItemSet 290728
*Dalmatica +1 augmented with Quickens+3% FC+6
*Moonshade augmented with Quickens+3%(If you're really crazy.)
*Iaso Tights augmented with Haste+4%
Max occ. quicken spellcast(+12%): I would use something like this if stun's recast/acc isn't that big of a deal.
ItemSet 298591
*Iaso Cuffs augmented with Haste+4%
Accuracy: if accuracy is an issue.