There are some large size dresses over on Encore Ballroom Couture. All the dresses are done in Swarvoski stones. http://www.EncoreBallroomCouture.com
I have a burgundy smooth gown by Kelly Kealy Mayton. (She designed a costume for Derick and his partner one time on Dancing with the Stars.) This dress is COVERED in dark red Swarvoski stones. It comes with Swarvoski earrings, a Swarvoski encrusted collar necklace and the KK travel bag. - I'm 5' 10". I've not sent this dress to Encore yet. Let me know if you would like more info on this dress.
Dress4Dance has big selection of plus sizes in all styles of costumes ready to be shipped.Dresses are not on the website but sales rep can always sent you pictures via e-mail uppon request. Here is and e-mail if you would like direct contact Dress4Dance@gmail.com
Since you said you were new to this - you need to know there IS a difference in prices with the different stones.
Korean Stones are cheap in cost and they are flat on the dance floor.
Percosea stones are a hair under Swarvoski. They have good sparkle factor, but most of the china manufactures don't use them.
Swarvoski have a high led contact and give fantastic sparkle affect the floor. This is where most of the money for a dress goes into it.
You need to also think about the resale value of the dress. Your not going to get much on a Korean stoned dress. Some people buy Korean stoned dresses and try and punch them up with Swarvoski. It looks like a band aid attempt and IMHO not that great.
I got lured into having a smooth gown made at Rainbow Shiu. I ordered it unstoned so I could do my own work. WHAT a mess! The Lycra material used in the dress top is flat and does not match the satin skirt color. The unstoned dress top was marked in glue spots! The boob cups are not put in evenly. The boning over the right breast rolls down. The shoulder straps are attached to the sheer sleeves NOT the body of the dress. The weight of the dress putting it on the mannequin to send me a photo already has started to pull holes in the sheer sleeve. I will not make this mistake again!!
I did have a good experience ordering a Latin dress from Star Dance Shop. Again I got the dress unstoned so I could do my own work. http://www.stardanceshop.com/
If you feel up to stoning your own dresses or adding stones to your dress(es) I've had a good expereince ordering stones from The Rhinestone Guy. He sells it all. http://www.rhinestoneguy.com/index.html
@ballroomchick - thanks for the great advice. I'm on the fence on whether or not to try stoning my own costume. It would save some money but also require a lot of time that I don't have to spare. Never anticipated this part of dancing!
You are, if not for the first comp, going to need a rhinestoned dress. And aside from the cost of stones, it's tedious work and requires experience and practice to put them on beautifully. The dresses are best if they are made to fit your body. Also, the designer can sit with you and discuss your likes and dislikes when it comes to decorating.These are all important factors when you shop for your very own custumes.