Gown with embroidered-looking top (scroll down – several pics of gown): http://translate.google.com/translate_c?hl=en&u=http://www.missnicaragua.com/01MWfinal.htm This gown seems most likely to be the one iRiShBaBe is talking about; though it appears in these photos to be white, the reflective fabric may have appeared blue on video as Ligia was moving around under the stage lighting.
Thanks, E.T., for posting that translation info from google; that helped a lot!