I've always done commercial work including a plenty of signs, some complex and painterly while others are simplistic and direct to the point (like the one shown here.) Yes, I invent and paint the lettering too.
The sign for Superior R.V. Storage is in Milton-Freewater, Oregon. I had started a frog craze there with window paintings of my original cartoon frogs depicted doing things somehow related to the business on whose window any particular frog appeared. I did this for several years, in conjunction with the Muddy-Frogwater Festival until the city manager high-jacked my concept. Sad but true, idea high-jacking happens a lot to artists and especially to those involved in the creation of commercial art. Still, I continue to create signs and other commercial art (posters, t-shirt designs, logos, etc.) and find it a pleasant break from the studio work.
Besides the sign shown here, I created two more large-scale permanent "frog" signs. The number of original cartoon frog art I created on windows numbered over 100 total individual works. Some businesses liked the work so well they left it up for years. I used high quality paint and proper technique so the window art lasted several years in good condition even though it was constantly exposed to the weather.