A slight twist on the original Musky Shrimp - I am sure many others have made similar upgrades:

Hook: Tiemco 2487BL or similar curved hook (size 14 shown)
Thread: Orange
Beadhead: 3/32 Copper Tungsten Bead
Weight: .015 non-lead wire
Tail: Natural Wood Duck flank feather fibers
Shellback: Clear Thin Skin or similar
Ribbing - Small Copper Wire
Body - Cream/Light Tan fur mix dub (or similar synthetic) dubbed on the thread with a modest amount of Gold-Brown Ice Dub over the fur

I prefer the additional weight of the tungsten bead and wire and seem to get most of my strikes near the bottom. The Ice-Dub/fur blend adds a little "life" to the body, and the thin copper wire adds a little more durability than using thread - I have landed 15+ good-sized trout in an hour with the same fly, and it was as good as new. Also, take your time and use a sturdy but fine needle to pluck the dubbiing to make the legs in each section of the shrimp. I have found sizes 14 and 16 ideal for most NJ/PA limestoners.