This talk of Sony 'pro' cameras is quite laughable. I don't see why any manufacturer would be stupid enough to compete with Canon and NIkon for the constantly shrinking 'pro' market. Although I'd agree, as someone mentioned, maybe the pro's they could be after are the dentists/doctors and lawyers.
When Minolta, Pentax, Olympus, Leica and Contax, with their extensive (film) systems developed over years and even decades, were ALL utterly incapable of competing with professional (film) systems from Canon and Nikon, why would Sony be able to do it now? A 'pro' camera is not worth a pinch of shit without a pro system (ie. all the paraphernalia required for customising the camera for a wide range of applications) and the support around it. Look at the Pentax LX, the Contax RTS series, or the Leica R8/9. Great cameras, great lenses, piss poor 'pro' systems and/or support (you need both). That's why Canon and Nikon are foremost in this field and that's why the likes of Minolta, Pentax, Olympus, Leica and Contax, all with beautiful cameras and lenses, were never able to get a decent cut of the pro action. Digital won't change any of that either.