Unfortunately I don't think I've ever seen such (and a quick web search yields nothing). What you can do if a regular (non-decora) light switch plate will fit over the shaft of the thing (probably does) and if so, you can get switch plates that will have one decora-sized hole and one regular light switch style hole (they sell them for bathrooms where there's a conventional switch and a GFCI). Obviously, you'll have to come up with the labelling yourself.

If you live in an area were swamp coolers are extensively used, the local electrical supply houses might be able to help you.