UIG Entertainment has released the trailer for Farming Giant coming to PC in October. It looks like an incredibly detailed sim. I think this is going to be one of those niche titles with a devoted but likely small audience. Probably not as small a niche as Garbage Truck Simulator, but we're talking some very micro level decision making, not unlike any other sim.
That said, the graphics look pretty good, the controls and details are there for it to be a solid sim, even if the subject doesn't make most folks jump up and down with excitement, it might be something I'd like to try. I was raised in a semi-rural community and worked on a hay and straw farm with my grandfather as a teen, so I could make some judgments about the accuracy of certain aspects of the farming simulation.
Graphically it might be ahead of Focus' Farming-Simulator 2012, but it's unclear if it has similar support for the major brands of farming equipment, which to many farm folks would be a key drawing point.