In theory it sounds great. There are a lot of different takes on this theme. I have quite a bit of sound therapy equipment which sends a specific frequency thru your body. I've found it to be relaxing and good for falling asleep. However, I have not found any of this equipment to have any effect on specific Parkinson's issues. So, thousands of dollars spent and really no therapy.

http://vibroacoustic.org/ - This company makes many claims but... I tried their product and got no results.

If you google vibration table you will find some pretty good sources especially for creating a table yourself. There are some interesting ways to hook up subwoofers to your bed and vibrate away. There are also "gaming" chairs that kids use to "feel" their video games. They are not very expensive. Another thought would be for you to check with your local gyms. A current fad is a vibrating plate that you stand on that shakes your whole body and is supposed to add to your workout. Some gyms have them and you might be able to try one there.
I'm a card carrying white rat and will try anything that doesn't kill me first but, these days I'm trying to be more careful with my money. I have too many boxes full of stuff (expensive stuff) that represent failed attempts to help my Parkinson's. So, I recommend free demos, samples and any other way you can try something without buying the whole cow.