Wife used to harvest various herbs and bag them in different forms for sales at our farmer's market stand. And a soap maker there often bought them for adding to her home made soaps and bath oils. But other than her and other individual customers we never tried to do any bulk sales. You might post this over on the Market Garden forum here as that is where the commercial growers and sellers hang out and they may have some contact info for you.

Dave

PS: and try the Herbs forum too for suggestions.

Also run a search in the Perennials forum. I recall a poster there had started a small lavender farm.