Italian Ice/Shaved Ice from Food Trailer

Good afteroon everyone.  I have been thinking, a very dangerous thing I know.   As I continue to convert my trailer from totally electric over to propane, I am considering adding either shaved ice or Italian ice as an additional item to offer.  I only do special events and was thinking along with the food items I offer, it may be financially smart to also offer either of the above.    It may also help to get me into some of the events I am interested in. 
 
My question to you, how much trouble to do either of these in addition to food.  Can having only one unit be profitable, or will it just be in the way? No experience with either.    With the heat in the trailer, can I still produce these items, currently I do not have ac.    Anyone have a source of information on equipment and supplies so that I can do more research.  
 
 Thanks in advance for your help.

I like Italian ice over the shaved ice. The only folks that I know of that do Italian Ice ended up making their own.