Something like this: robotmesh.com/9v-to-barrel-j … OgodHWQAIA
Except the wires need to be longer. I think Pololu can do work a LOT less expensively than other vendors, which is why I would really like to see Pololu make something like this. It would really help get my electronics kits evolve into robotics kits. I would also like to see an option for center negative barrel connectors, but center positive is fine.