Customizable @username twitter feed box


We are working on an application where use can create static pages of his websites.In our application we want the user to be able to change the @username handle to his preference and also adjust the font color and box style for his site.But I am unable to get such plugin or API.The developers sites have details about the widgets that work with key and username,but we don’t want the user to go and get a key.We want it to happen on the fly.
Similar stuff is present at http://app.imcreator.In the widgets section the twitter API allows to completely customize it.
We are looking for something similar.

Thanks for your time.