Quote - Hmm, and now that I see it like that I think it's a tad much for what I'm going for--I want more of a subtle shimmer than the more in-your-face shininess of sequins. Something that has sparkle, but isn't going to blind you if the light hits you. Something perhaps more like this:

http://2.bp.blogspot.com/_iyrya8fis-4/SyH7ZilEwwI/AAAAAAAACKY/yRisWeKiQFE/s400/vintage+SILVER+MERMAID+shimmer+dress3.jpg

http://static.becomegorgeous.com/gallery/pictures/carrieunderwood-2011goldenglobeawards.jpg 

http://media3.washingtonpost.com/wp-srv/photo/gallery/100504/GAL-10May04-4461/media/PHO-10May04-221648.jpg

http://www.myeveningdress.co.uk/82-256-large/dark-green-evening-gown.jpg 

I think the key here is I want sparkles, but I want it subtle and I want the look of soft fabric--as opposed to the over-sparkly and hard sequins. I'd go with velvet, but I intend to use velvet on a shawl over the dress.

 

Why don't you use a shimmery satin or silk?  Tabala had some shimmery satin materials and Fabiana has some great sparkly materials in her sets if you have any of those.