No.Not sure if these are "persistent enough", but there are some quite substantial contrails off the canards of the XB-70 at 2.05 and 2.20 - just for a second or 2 each. I wonder if they are actually smoke for airflow indication?
The forewings of a canard aircraft suffer a higher wing loading than the rear wings so that near the stall the nose of the aircraft automatically lowers. That wing loading (when exploited sufficiently) will cause a sufficient pressure (and therefore temperature) drop at the tip vortices to form a temporary trail in certain atmospheric conditions.
When the XB70 was lost (by one of its tailfins colliding with a Starfighter chaseplane) it went into a flat spin and a complete cloud formed above the whole aircraft as it fell.