It is inevitable. The last few years every manufacturer is returning to the .45 ACP due to a surge in popularity. Springfield is developing and promoting the XDm platform to check the market response before making the product. Based purely on the US market for .45 ACP there is no way Springfield will skip the opportunity.
I'll bet a cold one on it.. It's perfect competition pistol opportunity, with the match-grade barrel, nice "M" trigger, etc. and all the other "m" goodies... .45 ACP is coming, and it too will be all over the magazine covers. My prediction.
Work for a distributor and Springfield came and said they did not plan on making one at the time, but if everyone calls and creates a demand for one, one will eventually be produced. I don't think the grip can be made as small because the 45 has a longer case but it would be cool to get the better grip and match barrel with the target sights. Also the ability to disassemble the firearm without pulling the trigger would be awesome and a great safety feature.