I own several...
...snubbies in large calibers. I have two which I alternate for concealed carry. The first is a S&W 325 Nightguard. That large, alloyed N frame is easily carried, and I like the idea that I have six rounds available, and it's very much easier to unload/reload than a rimmed cartridge gun.
That written, my favorite carry wheel gun is a Model 696. While it's a five-shot revolver, it's not overly heavy, and the 3 inch barrel balances the revolver nicely. I carry two speed loaders, and I figure fifteen rounds is enough.
Smith discontinued the 696 in 1992, and hasn't produced another since. As others have mentioned, there just isn't a market. They do make a Model 296 Nightguard, so a concealable .44 special is available.
The market in handguns points to semi-autos, especially in the 9mm (parabellum and .380) size. Hi-Cap is a big seller.
Remember also, that a five-shot .45ACP requires different moon clips
eek
, different machining set up for the revolver, and most of all, evidence that a variation of existing revolvers (325, 296, etc.) would be successful in the market.