Here is a project I am taking over. A cocker Eclipse frame that was turned into a frame/rail combo by TimmyJay and XMT I believe. I'm like the 4th owner.
Lightestest you could probably get would be an XMT cf xule body with a cut down Lukes ultralight rail and have him ule mill the ygrip as well.
I have 2 almost new ones with screws. PM if interested. I'm curious to find out what you are doing with them.