Growing demand for metallic lightweight structural materials requires new design approaches, exceeding the potential of traditional material design. Besides merely low density ρ, a lightweight wrought product also requires sufficient high stiffness. As the density reduction of a material is usually directly coupled with a decreased young’s modulus E, conventional alloying is limited, even at elevated contents. The most promising material design strategy to overcome this detrimental relationship is the implementation of stiff constituents in a ductile metal-matrix, resulting in an increased specific modulus E/ρ. For liquid metallurgy production of high modulus steels (HMS) the Fe – Ti – B model system is currently of increasing interest due to the outstanding properties of in-situ formed TiB2. Nevertheless, materials production requires large quantities of costly Ti, which leads to the need for alternatives. However, due to almost unlimited stiffening compound possibilities, the selection of other systems is difficult. Limiting the reinforcement selection to Fe – B – based systems, literature and thermodynamic data are still lacking and materials’ performance mostly not well known. We present a combinatorial liquid metallurgy approach, utilising Fe – 10 at.% B – 5 at.% X (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W) systems, for alternative HMS design. Thus we obtained alternative model systems exceeding the mechanical and physical properties of the Fe – Ti – B system, thereby opening new possible pathways for material design. Comparisons of physical and mechanical properties are outlined and strategies for future alloy design discussed.