I had a friend tell me about the Slim Jim and it's notoriety amongst the older crew of fly fishermen here in Northern ME. After much digging, here's what I found for the N Maine variation
Slim Jim
Hook - Mustad R73-9671, size 8-12
Thread - UNI-thread 6/0 black
Tail - Red hackle fibers
Rib - Flat silver or gold tinsel
Wing - Two thin grizzly neck hackles tied in as long as the body flared outward and up at a slight angle
Hackle - Grizzly
Body - Black, gray, red, brown, or orange floss