Glocks
Any 40 S&W Glock will very easily switch to 357 Sig with a simple barrel swap and run just fine; though I'd also recommend adding a recoil spring with weight appropriately matched to caliber. You can use the same mags since the 357 Sig is just a necked down 40 S&W. Going to 9mm will require 9mm mags in addition to the barrel and recoil spring. As for going 9mm or 357 Sig to 40 S&W I don't know for sure if the muzzle opening on their slides will accomodate a 40 cal barrel, but at worst you'd just have to pick up an extra slide or just buy a 40 to start with. Otherwise the frames for all 3 calibers are the same size in each configuration (full, mid, and compact size). They don't sell them as a kit per se, but plenty of places online sell both Glock OE and aftermarket barrels, springs, mags, slides, and just about everything else you can think of for customizing a Glock. I don't see why the Springfield XDs wouldn't do the same, but it's far easier to get the Glock parts. You could theoretically also do it with a S&W Sigma; though I wouldn't know where to get the parts, nor would I put that kind of money into a Sigma. The Sigmas are good basic pistols, but not on par with a Glock or XD epecially for this type of thing. I would think that the Sigs, HK USPs, and CZs would also be able to this type of thing. However, beyond knowing they are quality pistols, I do not have any real knowledge on those three brands and will hence leave those answers to other members on this forum.
Edit: This might also very well be possible with a Beretta 92/96. I don't know if Beretta ever chambered either in 357 Sig, but if not an aftermarket barrel and spring shouldn't be too difficult to get.
