I used a "double barrel" switching arrangement, plus a push-pull volume pot. This gives me 17 unique sounds, but no copies - all positions are unique.
I used a rotary switch as my second 5 position so I wouldn't have to mod the face of my guitar. This replaced the tone pot that I never used anyway. But with a strat, you can have master volume, master tone, and the rotary switch.
I agree that splitting can be hit-or-miss, but if you choose the pickups carefully (and are willing to compromise a little on the humbucking sound), it can be very good. I use a Duncan Stag Mag at the neck, and an SK dualtone at the bridge. These (as well as Rio Grande's Tallboy & Muy Grande buckers) have one or more coils with alnico poles (like a single coil) - and it works well. If you don't want to have such limited options, remember that generally speaking, the higher output buckers split better.
http://www.guitarnuts.com/wiring/doublebarrel/index.php