Yasuo is a good pick, even appearing on this year's worlds. You can outduel squishy champions and escape through minions. His teamfight potential is decent even if you dont't have a team composition built around knock ups. Just use the new Trinity Force build.
More often than not, a champion is either a splitpusher or a good teamfighter. I guess you could have a bit of both, or a hypercarry that's good at everything in late game so he can be both a good teamfighter and splitpusher.
Good top lane splitpushers that don't suck too hard on teamfights would be Tryndamere, Nasus, Gangplank and Jax. They all have bad-ish early laning phase and start to hypercarry late game. Trynda and Nasus can be easily shut down in teamfights against certain teams though.
If you want to be able to team fight, avoid Tryndamere and Teemo.
Good top lane splitpushers that don't suck too hard on teamfights would be Tryndamere, Nasus, Gangplank and Jax. They all have bad-ish early laning phase and start to hypercarry late game. Trynda and Nasus can be easily shut down in teamfights against certain teams though.