When I have onions bolt, I harvest them and use them as green onions immediately as the seed stalk that arises will come up right in the middle of the onion and split it open. I don't know about selling the onions like that. I am not sure if the scape would bother your customers or please them or if they'd have no feelings about the scapes either way. You might ask at the market gardening forum if anyone sells their bolted onions that way.

Have many bolted yet? I noticed the first (and so far only) bolting one yesterday. It was one of the red onion varieties but I didn't check my map of the onion bed to see which variety, as I'm growing either 3 or 4 red varieties.

I have given my onions a "hair cut" half way through the season and used the tops for cooking.