These usually take the form of a fancy cooker designed for point-of-sale impact. The cooking section will often be surmounted by a glass-sided display compartment.
LPG gas versions are available for use in mobile catering units.
Popular makes include Victorian Baking Ovens (as illustrated) and King Edward. They are not particularly cheap, however we can offer good discounts from manufacturers' list prices.
Of course there is nothing to stop you using any standard cooker or convection oven for baking potatoes, and displaying them in one of the many heated display cabinets on the market.