I'm not a sleep expert by any means.. but since I believe anything is possible.. I think you could at least get by with 3 hours a day and still be fully functional.. (maybe less)
Here's my understanding of sleep.. this reality sucks

and the dream reality is the real one.. we recharge our battery's via sleep to be here in the suck, so yes I can see how important it would be you to recharge the batteries cause you don't like the suck.. but you don't have to define it as the suck and if you can do that.. you can get by with 3 hours of sleep or so I think it's possible if you don't attach definitions and negativity too it..
Remember too that it's the EGO mind always counting the hours of sleep.. maybe you should relax the counting never look at a clock and just do things that our pleasing and not make you tired..