Yes, the Arsat 30mm. But it is a rather heavy piece of glass at 1 kg. Putting that as your standard lens in medium format and then complaining isn't really logical. You only need to add a Sonnar 180/2.8 to your bag and you have a perfect boat anchor. (I know, I do run with such a setup from time to time)
Regarding a system or single camera, I would opt for a system. Even if it means starting out with a camera and single lens. It leaves you the option to expand if it fits. Of course that may mean putting up now with bulk and weight. If you say that you wanted wider often (compared to an 80mm probably) then you won't have much choice but to go for a system. Non system camera's are often limited to the standard focal. Unless you would go for the Fuji 690 series where a wide version is available. But that would mean a second camera if you want to go longer and then the weight jumps up more than with an extra lens.