A senior government source says the idea was drawn up by officials and has not been considered by the PM.
Clothing was the hardest-hit sector last year, seeing a 25% drop in sales overall.
Sunderland council chief Graeme Miller says it is "a vote of confidence for Wearside".
The chief rabbi has described the event, which was held at a school, as a "shameful desecration".
A 14-year-old boy has been arrested on suspicion of murder following the "inconceivable violence".