[nl]

>> [Amphetamine] allows you to stay up three or four days perfectly lucid

> Nope. No known stimulants negate the need for sleep

Technically true, but there is a whole class of non-stimulant drugs that do approach this level, without the weird, "amped" feeling of stimulant. Provigil (modafinil) is the best known of these.

Eg: Another study of fighter pilots showed that modafinil given in three divided 100 mg doses sustained the flight control accuracy of sleep-deprived F-117 pilots to within about 27 percent of baseline levels for 37 hours, without any considerable side effects. http://en.wikipedia.org/wiki/Modafinil

[rue]

That's correct, I used “stimulants” in the narrow sense and should have been clearer.

I don't have much information on modafinil or other substances in its class so I can't speak to it except to say that the early studies seem promising (I say this as someone who really, really hates the waste of time that is a good night's sleep) despite some reported side-effects.

I would certainly like to see more studies, as well as further information about sustainability. That is, it's great if it really does let you work reasonably well for 3-4 days (within 30% for < 2 days isn't really conclusive), but even then there's the question of what happens after. I doubt you'd just be able to sleep 8 hours and get right back on track.