American Hobby Products makes a nice one.
They have three sizes and then there are ones that measure torque and thrust.
No web site They advertise in R/C Modeler
Mail order only.
I have the Jumbo and it was 39.95. I just ran my Saito 150 on it last week but I've also used it with my Saito 100's, 91's etc.
The Jumbo will not fit 46 or smaller size engines.
I have a Carl Goldburg for that.
http://www.carlgoldbergproducts.com/stand.htm it's not safe for anything over a 61.
Enjoy,
Jim