Well, I am diabetic, and I know I have some peripheral neuropathy going on--mainly in my feet and lower legs, but when I get the vibration sensations, it's over most of my body, and it only happens (or is only noticible) when I'm lying in bed.
It comes and goes, and like sawa said in an earlier post, I thought it was the semi-trucks driving by my house! One time when I was experiencing it, I got out of bed to check, but no traffic...got back in bed, and it started again. I reached out to feel the bed, as it was kind of freaking me out, and the bed was totally still...that's when I figured out it was me!
I was so relieved when I saw people posting here saying they had the same thing. Interesting about the "tripping" angle, too--I've always been a klutz that way, but have had rheumatoid arthritis since my twenties, and it affects my feet, so I chalked it up to that, but maybe there's more to it. Interesting stuff!