Thanks to IBIubbleTea for starting this poll! We've contacted the vendor on your behalf and they've made the Sigma 18-35mm f/1.8 DC HSM Art Lens available.
I'd like to see a poll with Nikon mount Tamron/Sigma lenses included, as many are outstanding value over the Nikon brand equivalents. I just bought the Tamron 90mm 2.8 macro and can't wait for it to come in.