Any updates on this? I'm looking to build a mount for my 109 exMoD (already have a roof rack it came with, but set up with gutter mounts which I obviously don't have unless I got to hard top). I was thinking of using a set of rear ladders to attach to the cross member, the side antenna mounts and then a windshield frame mount similar to what you have. Just not sure if the rear ladders would be high enough to clear the soft top and not interfere with the rear flap at all.
I like how you're mounting the rear but I guess it would require a reinforced (new) rear hoop to hold it, where maybe the ladders wouldn't.