I bought an M7040 without the cab. Now I want the cab. Any ideas for good aftermarket cabs or know if it's possible to get a real Kubota cab and install at this point?
I agree.What you are wanting to do is a MAJOR undertaking!
You do not have a little compact tractor that's just a matter of bolting on a few panels.
One of the deal breakers is that M7040 have a lot of variances in years and models, old models do not match new models!
Most Kubota models vary from a cabbed model to a ROPS model.
The controls tend to be different and some of the mechanical parts are different or are in different locations.
The electric wiring is different the piping for hydraulics and water are different.
Linkages on a ROPS model tend to be solid bars where the Cabbed models tend to have cable controls.
An after market cab might take those variables into account, but I don't think anyone makes one to fit that model.
I think your best and probably overall cheapest option is to sell your ROPS model and buy a cabbed model.