WOW! Interesting set up. I don't think I've ever seen a three link done like that before. All the ones I've seen have the "Y" link on top of the axle, not under. Of course those were all in the the rock crawling world. Do you have any concerns with that lower link getting hung up on speed bumps, or curbs, anything like that? Hard to tell from the pics but it looks kind low to the ground.
I'll be following this for sure, I really want to see how this turns out. I've been toying with the idea of doing a triangulated 4 link on the rear of mine.