Provided circuit modules employ flexible circuitry populated with integrated circuitry (ICs). The flex circuitry is disposed about a rigid substrate. Contacts distributed along the flexible circuitry provide connection between the module and an application environment. A strain relief portion of the flex circuitry has preferably fewer layers than the portion of the flex circuitry along which the integrated circuitry is disposed and may further may exhibit more flexibility than the portion of the flex circuit populated with integrated circuitry. The substrate form is preferably devised from thermally conductive materials.