Recent success of learning for robotics has spawned much interest and demand for capable robot platforms that may eventually approach human level competence. However, current robot platforms for such research largely fall in one of two categories: static bimanual setups for manipulation, or mobile bipedal setups for locomotion — with a significant lack of bimanual mobile manipulators. We introduce Cone-E: an open-source, low-cost bimanual mobile manipulator designed to be a reliable general-purpose robotics research platform. Following the best practices in robot platform design for indoor environments, Cone-E integrates a compact swerve-drive base enabling omnidirectional motion, a telescopic lift mechanism affording a vertical reach range from the floor to high shelves, and dual 6-DoF arms to achieve whole-body mobility and manipulation. The design emphasizes modularity and reproducibility using off-the-shelf components, 3D printed parts, and open-source software, while remaining affordable with a bill-of-materials cost of $12K.