Nice idea, cheaper and easier to handle build than using a bandsaw but…chainsaws would mostly do a good rough cut and would waste some wood. Also you need a beefy chainsaw to cut some big boards. My 2 cents, its a nice cheap and easier to move around option over the bandsaw solution. Looks pretty straight forward to do too.
http://www.instructables.com/id/Chainsaw-Mill-Build-Use-Tips-n-Tricks/