I'd settle for even being able to sleep at regular intervals. I have a habit of staying up until I'm tired and waking up when I can't sleep anymore. As a result, I may stay up all day for several days and then stay up all night for several days. Or for several days, I may sleep twice during 24hrs, in completely random periods. I just don't do well with the concept of "well, it's 10pm, so that means it's time to get into bed".
Long live melatonin. Gave me a lot more control over my sleep schedule. Plus, the "positive side effects" section on the wikipedia entry is several pages long...
I've not needed to be anywhere at any particular time most days for about 8 years now. I sleep wildly like you mention, and often don't feel good for it.
I recently went camping in the Lake District, and as the camp sites were very dark at 10pm I went to bed, and as the tent starting getting hot at 8am I got up.
I felt great for it.
For me, I think my body needs a routine. Shame I can't get into that routine at home, despite trying.
I do have a schedule work-wise to keep, but it's not enough that it informs the rest of my life-style, I think. I work three days a week (nights, actually) for about twelve to fourteen hours. I telecommute, so it's not a huge deal and I could technically do my job at any time, but various persons have come to rely upon my availability during those odd hours to sort of bridge an informational gap across geographies if something comes up.
Part of the reason I spend more time in my own basement than any other room of the house is that it's dark down here (I've covered up the windows with blackout fabric) and it's very quiet. I don't hear the neighbor cleaning his RV or someone mowing their yard or loud cars going past.
I know it's unhealthy, but I don't really know of another solution (and from what I understand, it isn't enough to have a schedule - but you need to have a schedule where you're awake during the day and getting sunlight).
I had a weird experience where I was working night shift two nights a week while going to university. I was also writing for a MUD and my deadline was looming. A two week semester break occurred, and for that two weeks I lived in a strange four-hour sleep/wake cycle, broken only by my work shifts.
It was really strange to spend four hours writing, say from 6am, then sleep 10-2pm, get up for another four hours, sleep 6-10pm etc. Not sustainable, but was an interesting experience to have. Gave me an insight into how screwed up shift workers can get, too.
Each morning the sun shines in my face, it's uncomfortable to keep sleeping like that so my schedule is surprisingly regular now. I used to sleep like you in my previous condo's.
