Here is the low profile crossmember I built for myself.  I gained 1"  of clearance at the lowest point.  More importantly, "overall" there is much less low hanging material to get caught up on.

The crossmember is made from 1"x1" tubing, 1/8" wall.  When it was completed I put 1/8" plate on the bottom to keep the framework from getting caught up on rocks.  The plate where the Xfer case mount bolts up is made of 1/4" x 3" plate.

Instead of coming up with a new mounting system I utilized the factory mounting system.  Weight changed little, this one might way a few pounds more than the factory one.

I didn't take very many in-progress pictures, but I'm sure you get the idea how its put together.  This was absolutely custom... I started building in the middle, with the plate for the mount to bolt to, and work my way out to the frame.  When It was all tacked together I took it down, finished all the welds, and gave the bottom a 1/8" skin to help it slide over the rocks.