I screen-printed the text using artwork I created for it. I wasn't really going for authentic, but something that looked a bit less home-made than the trophy-engraved plates that were there before I re-did everything (see below).
Today (a few years later) I would probably have used our white-ink Océ UV flatbed inkjet printer to do the same thing. The tricky part is printing onto a folded/formed metal plate. It requires a jig, but the process isn't too complicated (and not at all if your plates are flat). Just search "Screen Printing" locally and you'll find someone who can do it for you. Screen-printing is how a lot of equipment is "printed". If you give the printer a full-size template of where all of your switches are and what you want the wording to be, they can look after the rest. It will cost a fair bit more than Dymo labels to complete but you probably figured that out already.
Yours looks fantastic Mark. I tell you what guys, if you want that look, let me know. I am sure the guys at Luftkraft could stencil and airbrush something just like that. After seeing Mark's, I might just have them do mine.
I finally got some pictures of my Pegasus Racing dash switch placards for comparison. Not nearly as nice as Mark's custom screen prints, but I like it much better than unlabeled and the cost was around $25. You be the judge!