I wouldn't so much look at Jim Henson himself Ken, rather his creations. ;-)
:-O :t:Grand Water Rail sketches.
I did check for rails in the Muppets and can confirm that there is one referred to in "Muppets at Sea" (should ideally have been Muppets in the Marsh)
"Lew Zealand leans over the rail and looks for a new boomerang fish."
http://www.reelcollectibles.co.nz/images/muppets/mr/muppets_master_replicas_gonzo_photo_puppet_replica_3.jpg
Great start to your Gonzo! I'm currently working on renaming all the birds of the Western Palearctic - Water Rail is now called "Lipstick-wearing Gonzo".