Small kitchens might be cozy but opening them up might not involve a whole lot of expense.  For small kitchens, add a skylight to open the ceiling to more light and visually expanding the space.  Likewise, removing any soffits above the cabinets will allow the eye to follow a wider ceiling.  Lastly, consider light colored cabinets; open shelves and glass-fronted doors give depth to the room and cook up a whole new look.