No pics, but I made one for a bud using his old Filson wool coat (olive drab color). IIRC dimensions were 8x8" with a 2" full length gusset and the flap a one-piece extension of the back panel. Per his instructions I added a leather pocket roughly 5x5" on the inside of the back flap. Out of curiosity and concern for seam strength, I went ahead and included leather welts. It actually turned out really cool with the dark brown (Tandy stoned oiled leather) welts against the olive. The 2" atrap was one I wove from olive and brown wool on a Inkel loom.
Overall I liked it well enough to want to build one myself, but haven't come across another coat in garage sales yet. That Filson wool is lots tougher and tighter than blanket wool, so I probably could have got away without the welts.