My artist wife got these nice drawing pens called “Design Twin Marker” a while ago in Copenhagen, Denmark. (As we found out later, it’s easy to order them on this internet thing as well, so don’t worry!)
When I played around with these I noticed that their shape and thickness are about as perfect as it gets for a magical paddle pen! Furthermore, the four rounded sides of the pen can be used for more than one transformation, like blank to brand name / to name of chosen card / to “Vanished!” message, at least when playing to a camera.
Just another idea. Give it a try if you are also a pompous, petty paddle peddler!