I feel like I succeeded.
There are quite a few tool boxes/totes which look similar to mine, but none that have the same versatility. Because of the two extended, parallel handles, I can easily clamp other items/cases to the toolbox--without it tipping to one side--and hold much more in one hand. The metal handles and a vice-grip pliers can also be used in a number of different ways.
The parallel handles also enable tools to be hung between the gap in creates, which allows it to hold more tools with easier access.
The two top cross-braces are spaced far away enough from the handles so a 2x4 or even a 4x4 can be rested on top and used to cut items if no other flat surface is available. The braces are skinny enough to be used for clamping. And if repeated clamping and cutting damage or dent the braces, they're the only pieces which use screws to hold in place and are easily replaceable if needed.
Most everything (except the previously mentioned four screws and polyurethane) was made using salvaged materials, making this project environmentally friendly and very cheap.
It's strong and probably took me two hours to build, over the course of two days.