Hey, I"m in the Miami area and I know some Dominican salons there. Since no one has replied, I thought I would. Downtown Miami has a few good ones: MetroBeauty, which is both a hair salon and a great beauty supply and make-up store. There are 3 of them downtown, and all have salons run by Hispanics, so they do Dominican blowouts. I also know another one that is downtown; it's Hair Gallery, not too far from one of the three MetroBeauty store/salons and it's pretty good too.
I've only been to the Hair Gallery to get my hair done, and it's $25 there, wash, deep condition and rollerset + blowdry, I think. I haven't been there in a few months.
For MetroBeauty, I think it's $30.
If you don't find anything else, and would like to try those, I can give you the addresses. By the way, I think most Hispanic-run beauty salons do blowouts...