Would it be posible that Sony will reply to the RED and Canon C300 offerings with a less expensive 4K camera with E-mount?
I hope so, it would be could for the market.

Lets see what happens at NAB 2012 next month.

The Sony NEX FS700 – 4K for $8k | EOSHD.com.

[Update]
Official Sony NEX-FS700E product page with specs and prices.