An electric lift system might work on a pickup sized bed, or even up to a 1 ton or so, but using one on a big rig bed would be sending a boy to do a man's job. Hydraulic is probably the only way to go on a truck the size you're working with.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!