Indeed, Ralph Page used to chant along with the music in quite a melodious way. Not sure if you'd call them "singing contras" since he wasn't always following th exact tune, but he did call some dances as one would a singing square, with plenty of rhyming couplets and with the calls coming at the same time as the action.
Here's an example he provided of how he'd call Lady Walpole's Reel. http://tinyurl.com/27zv8zm David Millstone
