Cool premise. You'll be taking up a bunch of room but hey if it works out...
I'd vote for projection. That way, others can see what you're experiencing. One way or another, you will want to make sure guests at a party can see what's going on. My driving cab draws them in like moths to a light. Now if I could only get them to use coasters on the Plexiglas roof.
A concrete tapper? Man, those things draw a lot of current. Your house will brown out when you play the thing. Have you considered base shakers, or maybe a homemade eccentric motor to vibrate only the chair?
On the Xcelerator thread (referenced in my footer below) I and a lot of others came up with some cool ideas. You may want to give it a scan.
Good luck with the project.