about time cough!
The makita style one seems good but you have to adjust the swingy bit for log size which is fiddly and not very slick. These two; "SawJaw" and "Timber Croc" seem like a breath of fresh air in this respect...
SawJaw 2010 002.AVI - YouTube
Timbercroc | Welcome
This seems alright too, different concept...
http://www.youtube.com/watch?v=6hrtK1uOVXM