Strikemaster sells a 6" LazerMag Express in a 6", but it's only one pound less (23#) in weight than an 8", so I don't see an advantage.
We have a 6" manual that only weighs 6 1/2 pounds and Doug can cut holes pretty fast as long as he's not dealing with a foot or more of ice. The Strikemaster people are very nice to work with - Roberta
http://www.strikemaster.com