I'm not, but there are plenty of things you could do. I think the Living Seas salon would be perfect for that, or if you wanted it to be outside of the park so you could have outside vendors, you could always do the reception at Ariel's. I know a few girls are using an Ariel and Eric cake topper, Lenox has a few, so just do a google search. You could also really carry the theme with your table names, placecards, centerpieces, favors etc. Shelley from Impressions can do custom Disney invitations so I'm sure you could have Ariel and Eric on them. You can request a sample from her, the samples are free. Her invitations are a little pricey but worth it in my opinion. Disney has done quite a few under the sea cakes. You could have Little Mermaid characters appear at the reception, be sure to check with Disney on that, I know there are some restrictions and certain ones can only appear together.
Hope that helps. I don't remember whose PJ it was, but there is definitely at least one on here that has a Little Mermaid theme, if you go to the PJ section and just read through a few, you may get some ideas.