Some do - e.g. Gavin Harrison. He's using a UK high end (and high priced) product, I've forgotten the manufacturer but this can be found on his thread here on DRUMMERWORLD.I don't think people thump thrones anymore. Do they?
I have & regularly use the BC throne, the same model Gavin uses. It's totally different to other thumpers that attach to thrones. The standard stuff is developed from surround sound seating systems, whereas the BC2 is a bespoke development for drummers. It responds precicely to the input from your bass drum mic. It even reproduces the tuning & exact sustain & dynamic reponses of your drum. It really is like hearing the real thing after a short time of adjustment. Tactile monitoring is so useful to me. Superb on stage without the need to increase stage volume, & gives you as much punch as a 2K drum monitor system, but without the bulk & cost.Some do - e.g. Gavin Harrison. He's using a UK high end (and high priced) product, I've forgotten the manufacturer but this can be found on his thread here on DRUMMERWORLD.
Before actually buying a sub kick system I'd try it out - it might come across as a great tool in ads but not really work out for everybody in reality.
EDIT
Here's the system Gavin uses:
http://www.porteranddavies.co.uk/
On his "Methods and Mechanics II" DVD, Todd Sucherman explains that he personally doesn't like throne shaker systems but rather prefers a monitor placed effectively so he hears/feels the low fequencies going on. There's several ways to get "more bass".