GX680III will do 645-6x8. It can also be used to hammer railroad spikes or as a wrecking ball if necessary.
We have a GX680(I) that students can check out -- I usually suggest that they not try to hand-hold it! The Rolleicords and the Fuji 6x7 see more use for that reason. But the GX680 is an impressive machine! Unless there are different backs, our early GX680 is just 6x8.
At least with LF landscape, a bad day of photography can still be a good day of exercise.