shifty,
I've handled a couple. The 7/8" barrel used allowed for a slimmer version of GRRW's Leman Trade Rifle. The Little Leman generally had a 13" or 13.5" LOP while the Squirrel rifle had a 14" LOP. I think most were .45 caliber, but some may have been made in a smaller caliber if the customer requested.
There's a nice one for sale on Gunbroker right now with fancy wood and double set triggers. Just do a search for "Green River Rifle Works" there, and it should show up. I don't personally know the seller, but have exchanged a few emails with him.