I have a L5740 and have fed a few round bales with it but I dont think it has the weight or traction to due much tillage work. Why not keep the little kubota for tasks it does well and get a large used cab tractor for the times the kubota isnt the right choice? Lots of large cabbed tractors all vendors on tractorhouse.
A mid 80's jd 4440 comes to mind
This the reason why I'm inclined to M8560. It's heavy enough (if necessary with an extra weight) to do some serious stuff and not to gigantic to clean snow and do some yard work (I know compromises
I like my L3800 and it's very nice and almost new but this winter it was brutal without cab and heat (I guess we all still remember what was the last winter in NA
US used marked obviously has more choices than Canada one but it's easier to have a local deal than fly half continent to just see a used machine. Plus extra delivery and border paperwork is another hassle.