It's possible. I used to have a friend that worked for a car shop. When people would add features like leather and/or sun roofs, he would install them. They literally just cut the roof and add the parts. I don't know how expensive this would be, but anything is possible for the right money.
I was offered a sun roof option when I bought my iQ. It was this Toyota part and would be installed at the parent Toyota dealership down the road. They wanted $1800 for it installed. I offered $180. We agreed to disagree.
Just had a Signature 750S factory style sunroof installed in my 2013 IQ.... Cole Brothers in Nashville TN. Retail price is about $1295.00. Love it!!!!! Also had cruise installed... Looks great and works awesome.
They leak they all leak! It doesn't matter if its factory or the best aftermarket one money can buy it will leak. Now if your car is a garage queen like mine then I'd say its a cool option, I even own a 2007 Honda ridgeline with a factory sunroof, but I keep that one in the garage too. Be careful if you choose this route of modifying your car, as you are cutting a giant opening into your roof, and if you try to cheap out it will only leak that much faster. Taz on here did his, he chimed in a couple posts ago he's probably got more info about getting one done here in the US than most of us.
Forget the sunroof in the picture Taz posted, did anyone notice the fold back mirrors on that iq a factory option in Europe. Let me just say thank you once again to the jerk who decided not to put that one on our us options, not to mention the rear disc brakes!!
Oh yeah in my rant I forgot three engine options, and a manual transmission. Thanks again oh wise idiot of bad choices. I would have bought the 1.4 turbo diesel with a manual transmission, folding mirrors and rear disk brakes in a split second. Did I mention the turbo diesel version can get nearly 70 mpg of fuel!!