Fuji is currently developing a professional mirrorless system that should have an even bigger sensor than the NEX cameras.
Bigger than APS-C? And maybe with a sweet hybrid OVF like the X100? Sounds like a digital Contax G to me. I think I'll put of any big purchases until I see what that's all about.
Sony NEX-5N 16.1 MP Compact Interchangeable Lens Camera with Touchscreen - Body Only (Black)