A store that sells a tractor cab is Sears. For example under the topics Lawn and Garden and Tractor attachments, listed is a Craftsman brand Tractor Cab.
Need to be a little more specific here.... I wouldn't direct you to the same place to purchase a Volvo cab as I would send you to purchase a Peterbilt cab. You need to give an idea of what exactly you're looking for.
A snow tractor is called a sculpture made from snow.
semi cab
A conventional tractor is what much of the world outside of North America refers to as a "bonneted" or "hooded" tractor. It has a hood which extends out in front of the cab. This is in opposition to a COE (cab-over-engine) tractor, where there is no hood.
Attaching a snow blower to your tractor can be a very effective way of heavy snow removal. The company Berco make a snow blower that is made to attach to your tractor. It has received great reviews.
300 pounds
in the cab by the brake
yes
You can identify a Massey Ferguson tractor because it has a red cab and bonnet and grey wheels.
One can purchase a Ford N9 tractor from various sources. Some of those sources are Tractor House, Phils Tractor, Kijiji, Craigslist, Tractor Works and Homestead.
One can purchase tractor seats online from the website Northern Tool. One can also purchase tractor seats online from other websites, like Deere, Tractor Supply and Farm Machinery Show.