IF I were to try something like that I think I would use an air cylinder and make the mechanism myself. If you have something sitting on it, or it gets hung you can't hurt an air cylinder. If you don't already have compressed air on the truck then this would be a less attractive option, but worth considering.

For an electric one, have you tried asking http://www.amp-research.com/
?

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-