Downhill Coasting?

This morning I was unicycling by a friend’s house, where i have not ridden before. The street had just the slightest slope, but I thought, "Hey, I’ll try some coasting anyway. I got a little ways, while gradually picking up speed, but didn’t pursue it further, since i decided to go down the street a ways, to a level area. Then when I was back home this evening, I noticed that the relatively steep street I live on was pretty much free of gravel and mud for the first time in several months so I decided I’d do some downhill gliding, before going back to the driveway to practice stand-up wheel walk and side ride. I haven’t glided downhill in a long time, but not practicing didn’t hurt, since I got twice as far as before, and at a higher speed than usual. It was then that I decided I’d try to coast downhill. After a couple of false starts, I figured out how to get into it, and I went off downhill about ten meters in two seconds, accelerating at a frightening rate. By this time, I had reached fifteen mph or thereabouts (I can’t tell for sure), so I bailed out. I tried it again with similar results. I think I could do it a ways, if I had a less steep hill, so I don’t have to worry about killing myself at thirty mph, the speed I sometimes reach on my bike on this hill.

Has anyone else had any experiences with downhill coasting? Would it be possible for long distances?