I'm having zero luck finding the link in my bookmarks for the particular company I liked, but there are many companies who will make up frames with any text you want, top and or bottom. Several different colors, fonts, materials and designs of the frames too.
I intend to have a custom frame for my van, so I'd better find it!
If I do find it again I'll post the link.
For now, if you perform a google search for "custom metal license plate frames" you'll receive a flood of results.