According to Fuji Rumors, Samyang (better known as Rokinon in the US) may be coming up with a new super wide-angle lens for mirrorless systems soon. While earlier rumors were talking about a 12mm f2 lens, Fuji Rumors now found evidence for a 10mm f2.8 lens. Either would be fantastic, though the difference between 18mm-equivalent and 15mm-equivalent is considerable (assuming the lenses will be made for APS-C systems and not for full-frame). Unless the 10mm is going to be a fish-eye lens, there are currently two comparable lenses with that speed rating (one for DSLRs and one for Leica M), and both are from Zeiss (and extremely expensive.)
The 10mm f2.8 lens is said to become available for most mirrorless systems, including Fuji X, Canon M, Samsung NX, Sony NEX and Micro Four Thirds, but will also be made for DSLR systems from Canon, Nikon, Pentax and Sony. There’s no official word on either lens yet, but we’ll keep our eyes and ears peeled and will let you know of any future developments.