Found a new one for me,  have any of you tried one of these???
http://www.amazon.com/Crescent-RapidSlide-10-Inch-Adjustable-Wrench/dp/B000TDFSHI

Mel

Mel,  Never saw the Crescent, but I think a company named Petersen made one like it back in the '70's.  They are no longer in business.

Mike

Mel, heres a photo of the Petersen version. It used a helix adjustment and this copy is a little balky. Had it apart twice and it still hangs up some. Maybe thats why he went out of business.

While we're looking at oddballs, there's these two models too:

The moveable jaw on this one comes all the way off and flips around for conventional configuration in case the alligator type isn't what you need.