I couldn't find one that I liked so I made my own. The image shows the sign face up, but it should be printed face down for best results, and is oriented that way in the 3mf.
The outer edge has two perimeters, but all other perimeters are single. This also requires an MMU or a handful of manual switching, sorry. If anyone is interested I can make a back plate with the letters raised for non-MMU users.
Update: Mar 17 2023
Added a back plate so that it has more integrity, also prints more quickly. Reduced depth from 3mm to 2mm, 1mm for text, 1mm for back plate. Also added a 75% scaled down version that prints in 2 hours instead of 4.
The author marked this model as their own original creation.