Design and create costumes for promotions
These could be customized by the customer to suit a particular event (i.e. for a product launch, a company may want someone in an outfit that looks like their product). The costume could be specially designed to suit the corporate image of the company. As a extra, provide the people to wear the costume at the event as well.
Using your own people will help ensure that resell or rented items are looked after. After the event, rent or sell the costume depending on customization and resellability. Let advertising agencies and public relations departments know about your service to help get your new business idea up and running.