Not a FCP "direct' information but with the purchase of Omneon - Harmonic (the makers of Rhozet Carbon Coder) have released a new version of ProXchange for Omneon, as this is a Server side application and more then likely out of anyone apart from Broadcasters it highlights that ProRES either a OEM or codec sale is coming to PC.
This in turn could open the door to future applications or transcoders .. interesting.
ProRes is already on a PC, but in playback only. This devices pay Apple a huge fee to be able to write to ProRes, something the average person would not do. All I'm saying is, I wouldn't hold your breathe for ProRes exporting on a PC.