This is about the lightest 6x7 I've used
http://photo-utopia.blogspot.com/200...3_archive.html

It also has a shutter button on the front that you can squeeze and have less tendency to jab they also come in 6x9.
I can shoot the above at 1/15 easily without blur.
But to echo what others have said technique rather than strength, don't jab.
I think my Rollei is best though possibly due to me holding it a waist height but obviously its 6x6.
Mark