Somewhere or other I saw a video of a portable mill that used a circular blade of around 18 inches or so in diameter. Its advantage was that could do a virtical cut on the out run, and a horizontal cut on the return run. My problem is that I can't find it! Can you help please.

Here is one version.

Mighty Mite Portable Sawmills (http://www.mightymitesawmills.com/)

Anyone ever used one of these?
chainsaw mill (http://www.leevalley.com/wood/page.aspx?c=1&p=20127&cat=1,41131,41139)

My neighbour at the cottage has one. He burnt out his first chainsaw... but bought a quality saw and is turning out some nice lumber.

Thanks to hkstroud and rtw for your comments