It's tiny, but not THAT tiny.
I've had a couple of 1911-style 9mms... the most recent being a Star Model B -- and a 15 rounder would have to stick out butt of the gun 3"-4"... In that case, the gun isn't a 15 rounder, they're just using a 15 round magazine.
For it to be anything but awkward, it would just about have to be a double-stack, like some of the Para-Ordinance or STI guns.
(I've got a Walther P-38, a Radom P-35, and just sold a SIG P-210-6; they all are single-stack 9mms, and their mags aren't that much shorter than a single-stack 7 or 8 round .45. I've got a couple of 17-round mags for my Browning Hi-Power and they're pretty darned WIDE!)
It might be possible to make a double-stack 9mm mag fit a .45 frame, but I'm still skeptical!
The quality of my custom Norinco is pretty good, and a friend has one that is almost box-stock and its a great gun, too.