RE: Looking for holder for chainsaw to cut boards from logs..
Really think that chainsaw fixture is what you want???? Think I'd seriously consider purchasing a good portable sawmill myself. Especially if I had access to logs of sufficient size to make lumber. At todays prices for good oak you should be able to recover the cost of your investment in a rather short period by retailing rough cut lumber.
Green and/or air dried lumber isn't the greatest way to go but there is a market out here for it.