Brian, curious what line of work you're in that requires you to carry? LEO? Or something else?
As for a good gun for dual use carry and IDPA with a caliber above 9mm, I'd STRONGLY recommend a Smith & Wesson M&P45 .... I LOVE MINE. I'm a decent IDPA shooter after about 10 matches over about 6 months, and actually shot three seconds FASTER (overall time) with my M&P45 than my M&P9 when I shot both at a classifier match (classified Sharpshooter with both - a few seconds shy of expert). The .40 S&W is a great caliber too (one I've carried for years), but if you get semi serious about IDPA I think it's a liability because it doesn't qualify for CDP class (.45 only) but shooting in SSP or ESP class you're competing against guys using 9mm with powder puff loads. If you're just doing IDPA for fun/practice, then don't worry about it. But if you're wanting to compete - a .40 is behind the curve in SSP & ESP mainly for the fraction of a second longer to reset for a follow up shot vs. a 9mm.
Regardless of which M&P you prefer, if your job allows, also strongly recommend trading out the M&P fire controls with a kit from APEX Tactical. Relatively easy self-install using the free YouTube videos they produce to walk you through it. I went with simply changing out the sear and striker block and left all the factory springs in both my M&Ps, this gives around a 4-pound trigger pull. But the DCAEK kit adds some springs that raise this pull weight back into the factory 6 or 7-pound range while keeping the added APEX parts benefits of overall smoother trigger action and more definite trigger reset point.
) .... I've heard quite a few stories of top-level shooters winning CDP division at regional meets with M&P45s, and shuttin' up those 1911 fan boys 
