I am guessing that you aren’t given a product that you must sell during this interview? If that’s the case, I have two ideas that I think might be of some assistance.
First idea: Sell the company’s best selling product.
The key here will be researching the company’s product line. Get every piece of information you can dig up on their best selling product, as well as any ancillaries or options that you would have on a real sales call for the company. Procure as much technical information as you can get your hands on, and then read and re-read them until you KNOW their product as well as they do. I would also find a few companies that are currently using the product, and include mentioning them as being entirely satisfied with said product. As it is a cold call, I would probably lead in with a introduction something like “Bob’s Boilermakers (the company you are selling to) does a lot of business with government contracts. I would like to have five minute of your time as I have a couple of ideas I would like to share with you that will make your company more profitable.”
Second idea: Sell yourself, as a commodity, to the company.
The key to this one is research, research, research. You will need to ascertain as much information as possible about the role you will be playing if you are hired by this company. My lead in here would probably be something like “Mr. Jones, as you know, your company sells $XXXX.XX dollars in commercial widgets every year. I have a product that I believe would increase that by at least XX% while also increasing customer loyalty…” Use figures based on your past success to back this up, and mention your references and satisfied past employers as testimonials and examples of your product’s proficiency in getting these numbers.
In the end, it seems to me that they are asking you to be creative an unorthodox. So, be creative and unorthodox!
Best of luck!
Bill