RE:Prawn and Shrimp imitations??
You know how I feel about my G.P.'s. There are virtually 3 patterns in my fly box - Black Marabou G.P.'s, Purple/Black Marabou G.P.'s and Orange G.P.'s. You have seen my Pecarry version of the Marabou G.P., but until recently my Orange G.P.'s were the Sean's Prawn version. I'm now working on a marabou version of mixed marabou in orange and red - its looking good. I much prefer the apparent bulk and action of marabou in the water over the standard tie. I also use Wooley Bugger Marabou to tie these flies - its cheaper and has plenty of length for the relatively short wings.
I also believe in tinkering with, and combining patterns and styles. Another recent variation borrows from your "Rat" and my subsequent "Chest Beast". It is in essence the zonker strip rat-tail with a Marabou G.P. style wing and body. This is a scary looking fly with a great silhouette and movement - I think it will, in the black/purple version be my "first light" fly of choice on the Thompson next fall - not to mention a good call on the Skagit this spring!
Tight lines - tyler