Some 10 years back I made a cab for my Mitsubishi MT180D.
It is kinda boxy looking but nice an warm.
Front and back windows are emergency exit windows from an old school bus that were free. I used the bus rubber mounting system (like old cars use)
The heater is also from the same bus, one that was under one of the rear seats.
The heater is actually made by Carter, about 6" X 6" X 3" and I modified it to use a 12 V computer muffin fan as the old fan was 6 volts, loud and drew lots of current.
The muffin fan draws a mere 1 amp or so and is much more efficient.
Luck provided me with both front and rear wipers at yard sales for modest prices.
Side windows are HD plastic as used in convertible rear windows.
I do recall that my cash outlay was about $200 at the time.
Just last week I replaced one of the side "windows" and that set me back $40.00
If I recall I had maybe all of 2-3 days work in the cab.
My frame is 1.5" sq tubing, etched primed and painted with tremclad.
All my panels are 16 g galvanized sheet cut on a sheer to size as is the roof which has a 1.5" fold down at about 100 degrees to act as gutter.
I made the roof somewhat longer than the frame to have the 'eyebrow look' as well as to keep snow/rain away from the glass, it also protects my work lights.
I opted for galvanized sheet stock as down the line I did not want a rusty old cab look, and that has proven to have been a smart move.
Today it is as nice as the day I installed it, however the tractor frame is starting to want some paint.
The flat sides/roof were attached with HD sheet metal screws.
B4 attaching my roof, I sandwiched a headliner to prevent condensation dripping as well as to prevent metal drumming.
The headliner also has some foam insulation that helps on cold or hot days.