I'm thinking GM already has an arrangement with an aftermarket supplier. As far as offering it in the first year, hey they have to have some reason to make you want to order a new 2010, 11, 12.
Now since they are also offering a canvas folding top (as a dealer ordered option?), I would think an enterprising supplier would figure out a way to insert a tinted plastic panel. Jeep Wranglers have had plastic side windows for decades, so a foldable see-through tinted top should be doable. It probably will come down to someone being able to make a good business case to develope it. I think a company called Bestop is the supplier for Jeep. Shoot them a letter suggesting they develop one.