If you've got only 1' past the hinge you probably don't need a latch up front, think of how much weight you'd have to set on the tail to get it to over balance?

I've seen those latches but can't think where to find them right off.
Have seen some newer trucks that have removable boxes, the box has jacks on it and the chassis can drive out from under it and under another, then they latch them in with what you are looking for. One of the trucks was for a window company, Pella I think.

These aren't the ones I'm thinking of, but are close
http://www.mcmaster.com/#catalog/115/2929/=3wdal3
bottom of the page, rated for about 4,000 or 6,000 lb.

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-