Rotational molding is a traditional plastic processing technology particularly useful for manufacturing large-sized and complex-shaped single-piece hollow articles. Over recent years, it has been deliberately modified into a technology that advantageously allows for creating a cellular structure, i.e., a foamed polymeric layer or core within the interior of the hollow molding that thereby encapsulates it entirely with a layer of solid polymeric skin with a desired thickness. However, the resulting extended duration of the mold-cooling segment due to the insulative effect of the developed foam layer or core within the mold represents a significant inherent disadvantage. Consequently, it becomes very difficult to effectively control the process so to retain a fine-celled foam morphology and skin thickness uniformity. To address these disadvantages, an innovative extrusion-assisted rotational foam molding technology has been designed, developed and recently patented (US 8,628,704 B2; Jan. 14, 2014). It is refereed to as Rapid Rotational Foam Molding. Presently, applying chemical blowing agents is a common practice and a mandatory routine in rotational foam molding plastics processing operations due to the intrinsic atmospheric nature of the process (vented molds). However, the newly-patented rapid rotational foam molding process is expected to advance the scientific knowledge in the field and influence the direction of thought and activity. This is so, because for the first time, it fosters engineering potentials for elimination of the blowing agent nature-related limitations in the manufacture of advanced ultra-lightweight multi-layered ultra low-density rotationally foam molded cellular composites. This paper attempts to identify the potentials of physical blowing agent-based foaming in low-pressurized processing settings, such as in rotational molding. The resulting new classes of ultra lightweight integral-skin rotationally foam molded cellular composites would be characterized with dramatically improved mechanical, strength-to-weight, insulative, and morphological properties that are currently not achievable.