I've heard of this, it's called the Uberman sleep schedual. It awesome, and the results i've read about didn't show any medical side-effects.

Still, in non-REM sleep our bodies heal and stuff. You aren't getting any with this.

There's another sleep schedual that's better for people who need to change the times etc. It's called Everyman. It involves one long nap followed by shorter naps which you can change within a 1-2 hour time frame if you need to. I was thinking of starting this, but thought about sleepovers, school etc. I thought it would be wierd if I were sleeping at school etc, so decided against it. I don't really need the extra time anyway.