BINGO! We have a winner, folks!
I have one of the Rockler models that I used to use on nice pieces - my wife got it for me a couple of years ago.
Unfortunately, I was at a charity auction a couple of weeks ago and saw three very, very poor pieces, all with the same stamp, all from different guys. I went home, looked over some of my first pieces, and it really made me think. Do I really want anyone to associate those with me? And did I want the same "Hand Crafted by..." stamp that everyone around here tends to use? Strikes me as disingenuous to the craft, the art, and the uniqueness of woodworking.
But...I'm just rambling. On a nice piece, I'll just sign it with a sharpie, date it, and maybe note wood contents. On a piece I'm not so proud of, I'll just give it away unmarked. My first Morris chair got no mark. The second got a proud signature and a pat on the arm. The penny idea - I'm using it. And I probably won't even pay Gary for the idea.