Custom Field for Marketplace checkout

Hi WPMUDEV!

I need to add a simple html drop down selection field to checkout where a customer can select their "reps" name. The reason for doing this is that the rep will then get the sale credit and will provide support to this customer. It doesn't need to be tied into any other functions. It just needs to provide the name on the order when it is sent. :slight_smile:

What is the easiest way of doing this?