I just learned of the 10mm XD's existence a few days ago. Its a big tease too as Springfield is running a promo where you get 3 additional magazines and a range bag if you purchase before Dec 31st. Oh to get in on that deal......
About a decade ago I had an XD tactical in .40 S&W and was fond of it, I'm confident that I'd like a 10mm more yet. If they made one with an even longer barrel I'd be on it like a dirty shirt.