I am not sure if this is what you are looking for but I use a similar service with a couple of my clients. This service allows you to change your number from your handset to any number (you will probably need to display your business name), record the call and (but probably wont use) change your voice. It kind of work like a calling card. But you be the judge of the service. Here's the sites address: spoofcard.com.
Hope that this helps.