here is the low down.
B50 is just an update to the B3000\B3030 cab, not the rest of the B-series
totally new cab. Iso mounts, right hand control panel, digital dash. much quieter.
26Hp model that slides under Tier 4, 33Hp model that has SCR
left hand brake
anything here thats Tier 4 has a big price increase. 3-4000 for the most part to pay for the SCR equipment.
there maybe more than this, I just kicked this out from memory.
I heard from a dealer something about a new B3150 when I called to ask about a B3000. I was also told the new B may be a bit bigger (but maybe that's just the cab), and since the motor is bigger, I have to assume part of that reason is to keep up with the current most powerful B, but also to possibly offset some of the power robbing that I expect Tier 4 may cause. All of this tells me the new B may have a decent price increase, which is what the dealer also surmised.
I have to believe there are decent deals going internally (between Kubota & dealers) to get the remaining B3000's moved out before the new model is introduced. I'm making this assumption based on the deal I worked out for my new B3000 and the trade-in on my B3030.
Since I don't really need to have the latest and greatest, and want the exact same size machine that all of my current implements fit, along with the Kubota pin-type QA that works with the 3 different FEL attachments I currently have, I didn't want to chance waiting to see what was coming. New right hand control panel probably is pretty slick, and I'd bet the much quieter cab is real nice, but I would be a bit concerned with a digital dash lasting decades without needing expensive repairs (I have all the latest computerized dash crap in my truck and worry that it's going to cost a fortune to repair when it takes a dump). I want my tractor to last and be simple to repair. But I'd have no use for a right hand control panel if I couldn't access it from the backhoe seat on this new cab model. Left brake would definitely be nice.
I actually do plan on keeping the B3000 for a very long time (I can hope), since I'm essentially sticking with the same machine as I have now, but simply adding a cab in this trade-in scenario.
Wife just asked me if I'm going to want the new model next year. I told her no. So I'm keeping my fingers crossed it's a big cost increase over the B3000 so I can be happy with the deal I worked out, and not want a new machine.