EDIT: Another official Cherry MX Blue RGB option has become available recently, the Cooler Master MasterKeys Pro L/S. This keyboard is not exactly new, but I ignored it for some time after the Cherry MX Blue versions were originally delayed. The keyboard is currently out and available for anyone looking at options besides the Corsair keyboard.
EDIT: Since I first wrote this answer, Corsair has surprisingly brought back the K70 RGB in Cherry MX Blue switches. They were available on Amazon a few days ago, but quickly sold out. Unfortunately, it seems these aren't going to be restocked, meaning the Strafe RGB is likely the best option for Cherry MX Blue.
The Corsair Strafe RGB is available in Cherry MX Blue switches, and is a great option if you cannot wait for the K70 RGB Blue. The reviews for this keyboard have improved over the last few months, and the one I tried had no problems.
One of the previous answers mentioned the G.Skill KM780 keyboard, and the KM780R RGB is now available for preorder, unless Amazon is lying to us. The RGB version of this keyboard probably will never be available for Cherry MX Blue switches. The Amazon pages for the KM780R MX Blue RGB no longer exist.
There is also the Poseidon Z RGB keyboard, which is relatively cheap for an RGB keyboard. This keyboard does NOT have genuine Cherry MX switches (Kalih Blue), and I would only buy this as a last option, because some complain about the switches breaking after awhile of use.