You might want to <A target="_blank" HREF=http://www.tractorbynet.com/cgi-bin/compact/showthreaded.pl?Cat=&Board=custom&Number=195684&page=&view=&sb=&o=&vc=1#Post195684>read this thread</A> about heated cabs.
I have a <A target="_blank" HREF=http://www.tractorbynet.com/forumfiles/47-194412-House%26tractor.jpg>Curtis hard side cab</A> on my NH2120. Works really well. Very toasty when you are working it, cooler on the open road traveling at speed. My cab did not fit quite as tight as I thought it would... better than no cab! I have front and rear wiper (no washer system), front cab lights (2), rear cab light (1), heater using engine coolant with 2 speed fan, a circulation fan (1).
Doors have slider windows. Doors can be removed very easily but a bit harder to put back on (not by much). I like the cab also becasue the tractor can be stored outside and not have to worry about the dash, controls, and seat getting wet or dirty.