The pen is probably salvageable, but will require a lot of drawing if you wish to keep it. My suggestion is to erase the shadow entirely to add a drop shadow later. You can use the clone stamp and the healing brush to redraw the pen. That will make it much smoother and eliminate your pixelation problem. I like the concept and the others have made some great suggestions. I'm not sure what programs you have, but like was suggested earlier vector tracing the pen image can make it look more like an illustration. The right programs can even do it for you if you choose to go that route. You've got a great start and I can't wait to see the finished product. Other than that, just shrink the signature. I don't agree that the font needs to change, because the objective is not to see it. :P