You might want to try Dianfine with your current camera to see if it will work for you. If is does then rent a medium format and shoot a roll and process it in Dianfine. In addition to typical press cameras you might want to consider a twin lens reflex such as a Mamyia C220 or C330. Very quit, easy to hand hold, and with waist level viewing great for kids, but the viewfinder is rather dim.

Paul