Of course, if you go on payroll, there is no incentive to take you off and allow you to buy in if the business is profitable. If you want to share in the profits, you have to take on some risk.
Why not rent the space, buy the meat, and take 100% of the profits? Build your brand and then you have some leverage. Having the other guy pay you like an employee with the option to buy in is great for you, but not something I would consider if I was in his shoes.