Solution 1:

One major issue with family names is that they can be pronounced however the family decides. Some pronounce the names as they were in the original language, some Anglicize the pronunciation, some Anglicize the spelling then adjust the pronunciation to fit, etc.

A good example of this is Stephen Colbert. He pronounces his last name koʊlˈbɛər while his father and brother use ˈkoʊlbərt.

Because of this flexibility, no reference will be able to tell you exactly how to pronounce any one person's name. The best they could do would be to provide an array of common ones.

Solution 2:

Within the limits described by the other poster (Dusty), these websites do this job pretty well:

  • Forvo (If the word does not exist, you can submit it and someone will pronounce it eventually.)
  • Ingolo

Here is Rumbaugh from Forvo.

You may also try the Cambridge English Pronouncing Dictionary (hardcover).

Solution 3:

PronounceNames.com which calls itself a "Dictionary of Name Pronunciation" has a good list and also takes requests (though its unclear how much time it would take to post a answer/suggestion)