I made an extention from the back edge of a cupholder in one of my old blazers. (I have an off roading background too) It was a metal brace which extended up to a velcro wrap that you matched to the size of the cup (since eveyone was switching the big sizes all the time back then) Never lost a top heavy pop ever again...

I do have a friend who's parents run a metal stamping business so production might be possible if there's enough interest.

What I'm thinking is a plate which goes between the top and first lower screws on the handle and then probably ties in at the bottom through one of the stock screws. (overkill, but I like that) Then it would have a commercially availible plastic bucket on the bottom and a velcro strap up near the crown of the cup.

Forming the bucket out of AL might be an option in a production run. The stock I have access to right now is tempered and I don't want to take the time to anneal it so I can bend it up.

 

After looking more closely at my doors in and out of the car (I have an extra set of door pannels in the living room) I'm modifying my proposal a bit. The cupholder will use the first two lower screws on the handle alone. (there aren't any screws along the bottom except the very back)

Should still be just as sturdy and won't interfere with the handle at all. (stealthier too)