It's a rather common phenomenon in English for words to change their lexical category, either by affixing (class > classify) or zero morphology (e.g., love was originally just a noun < Old English lufu but now is a verb, too). That having been said, what's wrong with text as a verb? It fills a need and eschews periphrasis. For what's it worth, texted gets 2.42M ghits.

Ceci n'est pas un seing.