Deidre Ann Hall /diːdrə hɔːl/ (born October 31, 1947) is an American actress best known for her portrayal of Dr. Marlena Evans on NBC's daytime drama Days of our Lives, which she played for 32 years. The character is considered an icon to the soap, and has experienced some of the most outrageous storylines in soap opera history. She is also an ambassador for Operation Smile. - http://en.wikipedia.org/wiki/Deidre_Hall
I don't think any other Barbie dolls were made based on the show, I was not able to find there's one.
Just as Erica Kane, Marlena Evans had her doll on 1999 as well. As I don't have the doll, these pictures are from eBay.
The doll is a recreation of Marlena Evans when she married John Black. Her dress is a very light blue (I wouldn't know just by looking at internet pictures) with a soft scallop trim, there's also a cascade of white tulle falling from her shoulders. She holds a nosegay of white flowers.
Hope you all have a great week!!