The Smittybilt one uses a rather small solenoid pack inside the large box, sort of like this one:
The easiest way to relocate it, is to swap the battery and winch leads. Mount the solenoid pack under the hood next to the battery and use the short leads to connect it to power (the leads that used to go from the box to the winch). Then use the longer battery leads to go down to the winch.
The plug it uses is the same as a standard XLR microphone cable. You can use a microphone extension cable (one male/one female end) and route the cable into the cab. That way you can either plug it in inside, or you can unplug the extension cable from the solenoid pack and plug the controller in right under the hood for outside use.