re: Would it be legal to design/produce your own license plate?

I bought a new Harley when I was stationed in England.
Even though I had my MC license since I was 15 1/2 in Commiefornia, I still had to take a safety course to get the endorsement on my military driver license.
Since I worked in the sheet metal shop, I made my own plate and put on some very high quality vinyl numbers and letters.
The bobby running the class noticed it right away and informed me of his displeasure in what I had done.
I told him it looked better that the crappy plastic ones that you have to buy from a vendor of The Queen so forget about it.
I was still pissed off I had to have parking lights installed and my reverse lights turned into amber turn signals on my '89 Shelby Z so it would be "safe" on their roads.