Until Zero is selling tens of thousands of units a year, it doesn't make sense to have factory options like this. They are trying to keep the base cost down. But so do other bike makers. Seats are best left to the aftermarket. Notice Kawasaki for instance doesn't have any seat options for any of their models, even their highest selling model, the Ninja 300. So I highly doubt Zero will ever offer one. It just doesn't make any financial sense. They make a seat that fits the tallest point under the bell curve for the height and shape of what they feel their average rider will be. If you're on the far end of the curve you get an aftermarket seat.
Has anyone that wishes the bike was an inch shorter tried the Corbin seat yet? It's only 1/2" shorter, but the shape at the front should be worth an inch or two or more when trying to reach the ground.
Also has everyone removed the preload from the front forks (easy with a 17mm wrench, or was it a 19mm?) I want to say there is like 25 turns of travel.
The same can be done with the rear suspension but best done at a motorcycle shop that has a spanner wrench.
And lastly you can slide the forks up in the triple clamps 1/4-1/2" by loosening the 3 allen bolts on each side and letting the bike fall down until it stops on the handlebars (but adjust your preload on the forks first as after you will be unable)
Get a boot maker to add custom 1/2" taller soles to your motorcycle boots
Although I think the seat from Corbin would be the easiest thing to try first