I've mentioned this before in the dim, distant past---an ice cream or
soft-serve booth with a freezer powered by a steam engine or a
make-and-break gasoline engine. Figured it would be necessary to cobble
it together yourself, but here is an Amish who makes and wholesales ice
cream and/or softserve powder---and a four-wheel trailer with a
make-and-break engine, looks like a monster White Mountain freezer.