A rebar forming apparatus includes a malleable material supply station for continuously supplying a malleable planar material and a malleable material forming station for forming the malleable material into first and second corresponding shell portions and related rebar products. The apparatus also includes a core pultrusion station and a cladding forming station for respectively forming core and cladding layers. A shell forming station is positioned downstream of the core and cladding forming stations which unites the first and second shell portions to form an outer shell with the core and cladding layers contained therein. The rebar product includes shell portions which are matably configured to form a disposable outer shell over the core and cladding layers. Related reinforcing composite product forming methods also include the use of a removable outer shell.