XSAN and 4K video editing

I currently have an Apple Xsan 3 deployment using Mavericks Mac Mini MDC Atto Thunderlink to FC, Promise 610f RAID with a JBOD and a Qlogic 5602FC 4GB switch.

I was originally looking to simply upgrade my storage as our editors are working in ProRes422 in Final Cut ProX without any issues. As our Promise RAIDs were going out of warrantly, I felt comfortable replacing the RAID and building a new volume on new RAID hardware. But then... I was told in the middle of 2015 we will need to be able to edit 4K. I did some Googling and see there is a wide variety of 4K formats. I am currently trying to nail down the format they will be using. I am also trying to nail down how many streams, I will need to feed to our edit stations.

Has anyone worked with 4K on an Apple Xsan? I am a bit confused on the requirements... from what I have read 4Gb FC is not going to cut it... 8Gb FC can handle some, but may have issues with some formats... 16Gb FC looks capable but the RAIDs I have been looking at use 8Gb FC.

Any input would be appreciated. I am in the Washington, Baltimore area.

Thanks,

Ray