Shenanigan (CRKT) is not assisted, but yes, other then that it's the closest I think you're going to get.
The Volt II gives you a bit more blade, but same problem with a smaller handle, same material.
Kershaw Whirlwind gives you more blade and handle, will have similar "bellied" handle ergonomics, better steel, but you also lose the flipper. Still gfn handle.
Kershaw Link is a good option, but certainly a totally different knife in design. Option of gfn or naked aluminum handle.
The other closest replicated "big brother" knife I can think of, that is all of the above; is assisted, flipper, and bigger in both blade and handle, but still similar in overall design is the Buck Momentum, which also comes with an s30v big brother blade, and a big brother price tag as well.
Kershaw Strobe is another non assisted that might be worth a look.