If you are still looking for this: Check out the app Number Saver. It is actually designed to do something different - it gives you a place to ENTER a number while on a call, and then dial it or save it afterward - but, if you launch Number Saver, it will pick up a number from the clipboard, and allow you to dial it. Great little tool. I'm going to make a donation - if you all like it, you should do that to.
BTW - I have nothing to do with the software or the author - I just think we should show our appreciation to app developers.
Dan