i haven't had the rubber piece for at least 6 months. anyway, someone around here sells them, so just do a search. definitely don't ship the phone off.
I lost mine awhile ago. Someone on this forum board has some extra self-sticking "bling" left over from decorating his/her 6700. They replaced the rubber joystick button with a ruby colored "bling". It looked pretty cool. They were nice enough to send me a couple. It works great. I've had it on there for some time now and it hasn't fallen off.
i just bought a pencil eraser refil. the size that usually is hidden under the cap. i cut it to the right thickness and glue it in there. great traction and works great. i used a white one so it looks nice