Larger cards were the locators of choice for early conjurors. Their use appeared wherever you found descriptions of card magic; see Charles Cotton's The Compleat Gamester, 1674, p. 118. Oddly, short-card locators were a much later development; see Jean-Eugène Robert-Houdin's Les Trickeries des Grecs Dévoilées, 1861, p. 99 of the Hilliar translation.
Within contemporary magic, Bill Severn published a technique to quickly make your own long card as “The Long One” in Bill Severn's Magic Workshop, 1976, p. 1, by applying Scotch Magic Tape to the ends of a card. This predates Gary Ouellet's Procontrol, 1986, which is a booklet focused on the same basic idea.