The 3 and 5 door canopies are nice for work trucks, you can get to anything in the bed thru one of the doors.
Ford Ranger Aluminium Canopy
Many canopy makers make these.
You can often find these at wrecking yards since most people prefer side windows vs doors, so they don't sell that fast.
Also watch for Rangers for sale with that type of canopy, seller might accept an offer just for the canopy, or a trade with a few dollars for your cover for his canopy.