Is the total still 51? I have found nothing on the Wiki or Forum to say otherwise.
If that is correct, 44 are known (not including the skills as they are still unclear)
The "Well Rounded" has been confirmed, so I can increase that to 45 known. That leaves 6.
There are 7 "noble" skills, so those last 6 can't be one for each.
Swordfighting
Jousting
Leadership
Trading
Bureaucracy
Oratory
Infiltration
Unless Trading doesn't get you one, since it doesn't do much?
I am just shooting in the dark now. Perhaps this will cause someone else to think of something.