This study presents a new micromechanical model that is simple, explicit, and directly applicable for broad engineering applications to predict the effective elastic moduli of very high-contrast component property composites containing high concentrations of particles. The approach is based on the Morphological Representative Pattern scheme, where the first pattern comprises a spherical fictitious inclusion embedded in an infinite effective homogeneous medium with physical properties of the matrix, while the others correspond to the classical three-phase generalized self-consistent problem. Instead of using the mean distance between particles, as addressed in existing literature, the volume fraction of patterns is calculated based on the maximum packing fraction estimated from the packing model. This approach shows perfect coherence with experimental data for benchmark examples of effective properties of suspensions of monodisperse particles in an elastic matrix and porous materials. Furthermore, a refined version of the model is proposed, which includes a free parameter representing the shape of the fictitious inclusion to evaluate the polydisperse effect on the overall properties of these materials.