I was tired too. It'* easy to lose track of the original intent of a topic, anyway
Take a look at the pic of that LS1 stuffed into the hybrid. Not pretty at all. Imagine changing the rear plugs. Imagine engine torque moving that motor. I know how far my L67 rocks under load. That would be scary.
I doubt it will ever happen. GM went with the L67 in the W-body lineup to bridge the gap after the F-bodies were discontinued. This is a much cheaper and more reasonable idea than an LS1.