Not for nothing, but Ive made some pretty neat stencils using my printer and a font called wingdings. Find the arrow "dingus" (wingdings and a couple other fonts arent letters and numbers, so open a new document, select the typeface you want and type A-Z in both lowercase and upper case, along with the numbers and characters over the numbers), print it out in the right font size (Id make about 15 arrows and make each one a different size, and try bold/italicized as well). Cut it out with a single edged razor, wipe your lite down with some alcohol and place your template over your light, spritz with your fav dark paint and viola! an arrow marked LED. if you want the reverse, IE a blacked out LED where the only part lighting up is the arrow, print and cut out the logo of your choice, now apply some double-stick tape, use a pair of tweezers to align your arrow properly (might want to pencil in some centerlines on the tape); press it on to the double-stick tape. NOW heres the trick part: lightly brush the arrow with either clear nailpolish, or even some superglue (you can also spray on a very very light coat of paint) to SET it. Let it cure and then trim around your "logo" with a X-acto or single edged razor. Spray with your fav paint (I used rattlecan Trim Black) and when its dry, pull up a corner with your razor and pull the design backwards over itself, this will keep from pulling paint with it. I used to make logos like this on my model cars all the time.
There are other things you can do...find a pic of a logo you like online, Shrink the picture to the size you want (print a bunch of different sizes and label them so you can hold it up to the car) and have it printed on clear plastic, trim it out, scrape the edges as thin as you can with a razor, and glue it on...shoot some lacquer or enamel clear over it and youre done.
Or; print out your logo on card stock, cut out the insides (like a stencil) and spray away.
You'd be surprised what you can use these things for, labeling a panel (instead of printing it out in block letters on white paper and putting tape over it. you can even make these templates and glue them onto lexan or plexiglas, then cut them out with a router or dremel to make different things.
I worked in a graphics shop and most of the "custom" work we did was this kind of simple stuff to cut out little doodads for hotrodders, and make logos for people. If you make your own design, even if its not exact, it cuts down on your design time immensely, which saves you money. Its finicky work, but that little custom "hotrod" script a lot of people pay 20 bucks for could be done in any font you, choose on stainless, and then epoxy some studs to the back (I'd take a piece of roundbar or something and round the ens over - try to give the letters some depth). Think outside the box, go to a modeling shop and maybe look at a lot of the Duplicolor rattlecan stuff; you really can make some neat effects, even though its Lacquer, you can spray some clear coats over them. The devil is in the details.
Sorry for the long post