Poly(propyleneimine) dendrimers with stearyl end groups are investigated as inverse micelles in toluene. While the initial dendrimers have a spherical structure with a collapsed core, solubilization of metal salt hydrate leads to the formation of cylindrical multidendrimer structures with swollen, metal-salt-filled dendrimer cores. The cylindrical structure can be deduced from the small-angle neutron (SANS) as well as from the X-ray scattering (SAXS) pair distance distribution function. While the neutron scattering leads to a two-step cross-sectional density profile, the X-ray scattering is sensitive only to the metal-salt-stained core. The gold salt inside the dendrimers was reduced to form colloidal particles, and upon reduction the cylindrical structure breaks up and spherical colloids are formed. The sizes are larger than would be expected if the gold salt loading of one dendrimer formed one particle, indicating that the ions from several dendrimers are combined. These dendrimer-stabilized metal colloids represent hybrid structures that have potential importance as selective catalysts and in the formation of composite materials with special optical properties.