Springfield Armory if you do this I will at once be joyful and yet pissed off.
There's an internet rumor that SA is coming out with an XD45 - a real .45 ACP, not GAP.
On the one hand I tottally doubt it. I don't think SA would go through all the trouble of tottally redoing the XD frame just to accomadate the .45 ACP. I realize that any decent engineer could easily accomadate the rest, and they could probably use the .40S&W slide if they enlarged the ejection port, but would they bother to go through all this trouble? Honestly, there's a reason you don't have as many choices in .45 ACP. 9x19 is cheap, and you can fit 40 S&W and .357 SIG on the same frame so your engineering cost is nil.
On the other hand though, I know if they wanted to, they could do it. Their competition offers double stack Wonder 45s. The problem is I think the G21 already has that whole market saturated, and from what I understand the G21 is mostly sold to hardcore competition shooters and LEOs. The LEO market is huge and they're not going to get away from their Glocks at Glock's ridiculously low LE prices. Springfield may have meant the XD as a service pistol, but I know of no LE agency that carries it.
If it shows up at the SHOT show I'll be simultaneously pleased and ticked off at the same time.