Hi Sonja, the short answer is yes, http/.//www.britroyals.com/stewart.htm. has all the information on the Royal Stewart's.
STEWART is a Scottish surname (also used as a masculine given name) Possibly of pre 7th century Old English origin, derived from Stigeweard the gentive prefix Stige meaning "hall" and the suffix weard meaning "gaurdian" or "warden". an alternative spelling is Stuart, this is French pronunciation as there is no consonant "W" in the French Language.
James I through James V had mistresses with issue, Legitimate or illegitimate would be given positions the in church or Kingdom, always in service of the King. some went to Ireland, several were imprisoned in England. also there are Scottish Clan Stewart. lands through out the Kindom, for example my surname is Stewart, my ancesters Stewart's lived Midlothian, Peebles and and the Borders. It is however the Maternal side of the family which provides the most historical interest, I am a decendant of The Black Douglas, the Douglas family were extremely powerful during the reigns of James I James II . The best way to compile your tree is to start with known ancesters .one other thing that you will find invaluable is to enter maiden names.