Im a plat 5 Warwick OTP with over 700k mastery. I've spent most of that time exploring alternative builds, or, as I like to call it, diving for ELO. These are three interesting and effective builds that I have created. All three builds take advantage of Warwick's scaling with movement speed on his global W passive and ultimate. Enemies wont be able to react to ultimates coming from the fog of war.

1) Does your team have one or less AP champions? Play North Korea Style.
2) Hit hard, hit fast, and hit often. This build snowballs incredibly hard, but has difficulty farming and clearing waves. It is critical to get ahead in the early/mid game.
3) Look for easy picks and dives. Camp your winning lane(s) to get early turrets and dragons. It is amazing how many kills you can get from low health enemies backing under turret. They do not respect the movement speed and ultimate range.

1) Does your team have one or less AD champions? Play South Korea Style
2) Counter jungle, gank, and counter gank. This build relies heavily on understanding your opposing jungles movement. The bonus gold from your Poacher's Dirk will help you stay relevant longer.
3) This build peaks in the mid game when a few turrets are down. Assassinate weak splitters. Even split push yourself from time to time. You are an excellent cleaner thanks to your speed and consistent dps.

1) Does your team have one or less tanky champions? Play Fat Korea Style.
2) Maximize mobility and health to take advantage of the ZZ Rot Portal.
3) Quickly split off from your team, clear a wave with Titanic Hydra, and place your ZZ Rot Portal. Rejoin your team and force a fight. Rinse and repeat.