Thanks to SS we know that Angelica Mandy confirmed at the London Film and Comic Con, during a talk with James & Oliver Phelps, that she would reprise her role as Gabrielle Delacour in Deathly Hallows.  According to the source:

She even likened the wedding of Bill Weasley and Fleur Delacour, the filming she will be involved with, to the Yule Ball scenes in Goblet of Fire, since it will feature ‘a lot of people’ and be ‘a lot of fun’. She also mentioned that she’s excited to return, particularly because of the similarities.