Been lovin my XD 45s for several years and my XDM for the last year.
Great news that SA is finally getting around to the 10mm in the XDM. Last summer I asked the SA rep in my LGS why they were dragging their feet on the 10mm. He said they get lots of requests for the 10mm in 9 states (likely all out west), and hemmed & hawed that the market was small.
I said that Glock sold every G20/G29 they made, and I'd bet a bunch of them were in those 9 states. I told him it was a shame that SA gave up that market share to Glock. He didn't have an answer to that.
I suggested that SA make a 10mm XDM like the old Tactical 5" to compete with the G20, & a XD-S or XD subcompact to compete with the G29.
Take the current .40 S&W XDM 5.25 Competition fill in the slide cut-out for more slide weight, a 10mm barrel, stouter spring system, and a new mag follower and there you would have a full-sized XDM 10mm. A .40 S&W XD subcompact in 10mm would need most of the same mods.
A SA 10mm may not sell as many as a 9mm but they should sell every one they make just like Glock does.