Two-component Fermi and Bose gases with infinitely large interspecies s-wave scattering length as exhibit a variety of intriguing properties. Among these are the scale invariance of two-component Fermi gases with equal masses, and the favorable scaling of Efimov features for two-component Bose gases and Bose-Fermi mixtures with unequal masses. This paper builds on our earlier work [D. Blume and K. M. Daily, arXiv:1006.5002] and presents a detailed discussion of our studies of small unequal-mass two-component systems with infinite as in the regime where three-body Efimov physics is absent. We report on non-universal few-body resonances. Just like with twobody systems on resonance, few-body systems have a zero-energy bound state in free space and a diverging generalized scattering length. Our calculations are performed within a non-perturbative microscopic framework and investigate the energetics and structural properties of small unequalmass two-component systems as functions of the mass ratio κ, and the numbers N1 and N2 of heavy and light atoms. For purely attractive Gaussian two-body interactions, we find that the (N1, N2) = (2, 1) and (3, 1) systems exhibit three-body and four-body resonances at mass ratios κ = 12.314(2) and 10.4(2), respectively. The three-and four-particle systems on resonance are found to be large. This suggests that the corresponding wave function has relatively small overlap with deeply-bound dimers, trimers or larger clusters and that the three-and four-body systems on resonance have a comparatively long lifetime. Thus, it seems feasible that the features discussed in this paper can be probed experimentally with present-day technology.