Kits for constructing a modular merchandizing unit include panels, frame members, joint pieces, and a cooling device. The frame members have a lengthwise shape defining outer and inner panel mounting assemblies and a joint capture region. The mounting assemblies include opposing legs extending from a base web to define a panel engagement region. The joint pieces each include a block core and orthogonally arranged plug assemblies projecting from faces of the core. The plug assemblies mate with the joint capture region. Construction of a unit from the kit includes the frame members retaining selected panels as paired inner and outer panels within corresponding engagement regions. The joint pieces interconnect the frame members and paired panels to form a cabinet. The cooling device is mounted the cabinet. A door assembly can also be mounted to the cabinet. Optionally, foam insulation is dispensed between the paired panels.