Market... I've though about that too and for dead people probably not much of a market. Now, would it be applicable to hearing folks to have a vibrating alarm for proximity, etc? I think so.
To wake up in the morning I use a product called "lark". It's actually marketed to hearing people and has been very successful. I've had it for a couple of years and love it. I've thought about how great it would be to adapt it to sailing instruments. On occasion I also use a vibrating watch to wake me. Again works well as it doesn't wake up the "wench" too..