I want to starting a small Kingsnake breeding business but I'm concerned that the snakes will stink. Of course I'm going to clean the cages every time they relive themselves (all snakes are going to be in sperate cages). will the smell linger in the room, even with regular cleaning?

If you're going to breed any kind of animal, there will likely be some odor. You can't possibly clean the cages every time they relieve themselves.
The most important thing to find out, though, I think, is whether you CAN breed kingsnakes in your area. Check your municipal and zoning codes before you go much further. They may limit the number of snakes you can have at one time, and may not allow you to havea home-based business at all.

it probably depends on the snake. i have had a ribbon snake(garter snake family)for more than 7 years. i only clean her cage completely about once a year. she does'nt have a smell.

I agree, misty. It depends on the creature, and the number of said creature that you have in a location.