I hope no judge would ever accept that, but I'm sure there's some corner of 'Murica where that would fly. I would think there would be due process problems with something like that, personally. Could you say, "I don't want due process"? No, but then again, I'm against the death penalty.
how is due process violated if the defendant proven to be of sound mind? life in prison, perhaps in the horrors of solitary, is not obviously preferable to non-existence.
there was a letter written a few months ago by a guy who was convicted of murder and sentenced to life w/o parole here in NY (effectively a non-death penalty state). he's been in solitary for 25 years and spends 23 hours/day in a cell, never gets to see the sun, etc. he wrote that even if the execution caused him a month of the most insufferable physical pain, he'd still prefer it to his current situation.
I'm against the death penalty as well, in the sense of executing people that don't want to be executed, but even execution doesn't offend me as much as these practices of forcing suicidal, life-term prisoners to stay alive via force-feeding and other forms of torture.