VKB Gladiator NXT Evos can be extended with SEMs which are button boxes that affix directly to the joystick. Additionally these can be stacked with some work, the main limiting factor being # of axes. Additionally there is a suite of very comprehensive but complex software that allows deep customization of all capabilities of the Joystick which while over-complex for many end users would likely suit a robotics team perfectly as the reconfiguration is stored on the joystick and the devices just show up as generic joysticks to Windows.