The press releases state Fuji mount will come, the website doesn't... It only says Canon, Nikon, Sony, 4/3. I hope I'm wrong but I remember a number of flashes advertised as compatible with Panasonic/Fuji a while back, but the mentioned models were only super zooms and other compacts.
I would love Nissin to release a flash that works in auto mode with the X-cams and I think the i40 would be a perfect match as it's small and has almost the same control layout as the EF-X20. But I fear the Fuji mount only means full manual :-(