You're pretty much already doing it - to get that nice sweep going, wide-grip pullups are king. You should make them weighted pullups if you can. Other than that, do heavy rows and I would even say deadlifts hit the lats to a certain extent.
I remember once at the gym someone asking me whether he should do his pull-downs wide or narrow. I told him to use a wide grip for a wider back and a narrow grip for a thicker back.
He must have sat there with a 'deep thought' expression on his face for about 20 seconds before reaching up to take a wide grip.
Grow your delts, too. It all helps with that V-shape look.
Also include some rowing so you don't forget about your mid traps and rhomboids. If you get the chance lie face down on a bench w/ a pair of dumbells and do lying rows. I find this exercise to be good if you have lower back pain, and not restrictive in movement like chest supported machines.
Deads, Chins, Bent Rows (barbel!) and a pullover cover all of the bases. Big traps are built by heavy overhead presses and cleans. Add to these dips, benches, toe press and squats and you've got your whole body covered.
wide grip pullups and bent bb rows. if its lats youre after, make sure your upperbody is as close as you can get to parellel with the floor. as rows are a great overall mass builder, parellel rows really heighten lat involvement. lat pulldowns can be a good finisher, but definitely hit wide grip pullups and rows first.