Kitsch-Slapped was the site to find the video below, where you can watch an interview with Vikki Dougan. She only mentions she was told by someone she was the inspiration for Jessica. So, needless to say this is still quite the rumor, as we've not heard anything about this in past 25 years (although it's worth mentioning it was recently revealed that actress Alyssa Milano served as the inspiration for Ariel, the Little Mermaid.)
There was original Roger Rabbit concept art on eBay that appeared to be authentic based on all other characters, but it also revealed what may have been the very first Jessica Rabbit art ever. You can see Vikki and Jessica are quite similar from the photos. Take a look at the form and shape of Miss Dougan, she certainly has a Jessica Rabbit appeal, so anything is possible. However, the movie filmmakers themselves have always credited Rita Hayworth as Jessica Rabbit's inspiration.