In a very welcome announcement today, Sony have stated as part of their on-going commitment to making the F5 and F55 cameras as versatile and flexible as possible and following customer feedback there will be a hardware upgrade option for both cameras that will allow you to add the popular ProRes and DNxHD codecs to the internal recording options.
This is great news, although I have to say I really like the XAVC codec for acquisition, as it will really help those still using FCP7 and provide the cameras with a codec for just about every possible scenario.
No details of when, or how much, but great news. You can find a few more details here: http://community.sony.com/t5/F5-F55/Announcing-ProRes-and-DNxHD-support-for-both-F5-and-F55/m-p/293988#U293988