haven't used beaver hide, but I have used lots of rabbit hides. they are cheap if you buy them at faire or vous and/or readily abundant if you hunt. They seem only to last me a season per hide but they keep my tootsies toasty. Anything much thicker and my shoepacks wouldn't fit comfortably either so I guess maybe necessity is the mother of invention for me... I'll look forward to what others have to say on the subject... I'll probably be makin new packs next summer.
z