There have been numerous attempts at creating overshot loaders down the years. Patent records from the late 50s and early 60s show as much, but none have survived in the market.
A major manufacturer recently registered a provisional patent of their version of such a loader, illustrating that the search for a workable design continues. A google search of overshot loaders offers insight into some of the early attempts.
Gurtech’s cam-based design uses modern hydraulics and drivetrains in their provisional patent. The company has built a low-budget prototype with the objective of proving that their 10 tonne machine can be as productive and more cost effective than a standard 15 tonne articulated wheel loader.