I'd say that the likelihood is bleak. They'd make a 9mm before they ever considered a 40S&W, and I don't see that happening - even if I don't necessary agree with why not. It at least seems like a 40cal would fit safely though, but I haven't ran the numbers on the 40's dims (I have spec'd numbers for 45cal, .45acp or .45Colt wouldn't fit - Colt rim physically won't fit, and the cylinder wall isn't thick enough for either).