A restricted layout region includes a diffusion level layout that includes a number of diffusion region layout shapes to be formed within a portion of a substrate of a semiconductor device. The diffusion region layout shapes define at least one p-type diffusion region and at least one n-type diffusion region. The restricted layout region includes a gate electrode level layout defined to include rectangular-shaped layout features placed to extend in only a first parallel direction. Some of the rectangular-shaped layout features form gate electrodes of respective PMOS transistor devices, and some of the rectangular-shaped layout features form gate electrodes of respective NMOS transistor devices. A total number of the PMOS transistor devices and the NMOS transistor devices in the restricted layout region of the semiconductor device is greater than or equal to eight. Additionally, the restricted layout region corresponds to an entire gate electrode level of a cell layout.