So, after I didn't like anything I tried, I decided to go with a Telvanni mage (Altmer most likely), who will live in a Telvanni manor, with a laboratory in some caverns below. While the island doesn't have a tower, I did use the tower model (you can't make a Telvanni locale without one - it is in their name after all

).
Some exterior work (click the first two for larger versions):


