I need to make 300 cupcakes June 18th in Chicago. 

I do not want to experiement and make it from scratch.  Does anyone have any recommendations on ready made specialty cake flour that professional baker's buy or any brands I can buy. It would also be good if I can just buy it online, any recommendations?

Also, does anyone have any light icing ideas?  I am not a fan of buttercream since its so rich.

Any suggestions on what I can add to the already made cake flour to make it more moist?

ADo you mean cake mixes? I think you can buy bulk cake mix on webstaurantstore.com. Also consider just looking for sales at your local grocery and stocking up. There are several doctored cake mix recipes, too, that use sour cream, etc to make it more moose and/or taste a bit better. Look in the recipes forum or do a google search. I bake all from scratch so I don't have any go to recipes.

Swiss meringue buttercream is not as sweet as regular buttercream, but it is buttery so you may not like that. You might prefer a more whipped cream kind of frosting. Again, you can do a google search for recipes. For pre made, try to find Pastry Pride or Bettercreme.

ARestaurant Depot sells 50# bags of cake flour for about $15, they have locations across the US.

In the Chicago area, GFS sells "pastry" flour in 50# bags for a very reasonable price--and they have several locations.  Now I am not sure if it is the same as "cake" flour, but I use this in all my recipes calling for cake flour and have excellent results.  GFS will also order in high ratio shortening if you ask.  PM me if you have any questions about where to buy ingredients.  I am in the northwest suburbs.

Sheryl

APastry flour has a slightly higher gluten content than cake flour (9% vs. 7-8%). For most recipes they should be interchangeable without resulting in a significant difference.

It sounds like you want cake mixes, not cake flour, or am I misunderstanding? You said you don't want to make them from scratch.

Yes, I am looking for cake mixes not cake flours sorry.

Do you guys know of any cake mixes I can buy that come out moist? Or maybe somethign I can add to cake mixes to make it moist? 

I need to make 300 cupcakes the day before and want to make sure they stay moist.

Thanks for the clarification, Jason.  I knew if anyone would know the difference, it would be you.