If your email client allows it, you could always just use an image to express your out-office sentiment, like this one. After all, they say that a picture is worth a thousand words — and visual content is still essential to successful marketing.
In this image, you’re letting people know you’re OOO with a “Missing” notice on a milk carton. Genius. Just be careful — this sort of autoresponder is best for internal emails, not for autoresponders that get sent to prospects and clients.