Welcome to the forum. A few posters from years ago were talking about modifying the existing doors into half doors. You may want to search for that - the idea would possibly be having 2 sets of doors - one for summer, one for winter, etc.
Edit: here, check this out - may not be street legal, but check out what the guy does with the doors - removes them and has structural tubing in place which would be ok for off-roading:
Any "half decent" body shop would/should be able to take a set of stock doors and turn them into half doors - the challenge for a US owner is going to be finding a body shop willing to accept the liability - their concern is going to be the possibility of litigation if/when the vehicle is involved in an accident.