ADD MORE button for textboxes

Hello,
Let me offer an idea to improve RSDirectory edit form.
Imagine you create a "business card" form.
Sometimes a user want to add 5 phone numbers, but sometimes only 1.
But anyway you have to create 5 textbox fields for Phone numbers (Phone1, Phone2 etc) and place ALL 5 fields on edit form.
Such a quantity of the fields makes an edit form visually heavy and overloaded.
Much better if you visually have only 1 Phone field and "ADD MORE" button if a user wants to add more (something like for image field)

Technically it can be implemented, for example, using the following way.
Let's say on admin side - field edit form - we can have a possibility to ASSOCIATE any textbox field with other textbox fields.
If we associate Phone1 textbox field with other Phone2, Phone3 etc - then on edit form will appear "ADD MORE" button.

This case we can seriously ease an edit form from visual loading of ALL fields.
Thank you for your attention,
Best regards
Serge