This paper presents FabricKeyboard: a novel deformable keyboard interface based on a multi-modal fabric sensate surface. Multi-layer fabric sensors that detect touch, proximity, electric field, pressure, and stretch are machine-sewn in a keyboard pattern on a stretchable substrate. The result is a fabric-based musical controller that combines both the discrete controls of a keyboard and various continuous controls from the embedded fabric sensors. This enables unique tactile experiences and new interactions both with physical and non-contact gestures: physical by pressing, pulling, stretching, and twisting the keys or the fabric and non-contact by hovering and waving towards/against the keyboard and an electromagnetic source. We have also developed additional fabric-based modular interfaces such as a ribbon-controller and trackpad, allowing performers to add more expressive and continuous controls. This paper will discuss implementation strategies for our system-on-textile, fabric-based sensor developments, as well as sensor-computer interfacing and musical mapping examples of this multi-modal and expressive fabric keyboard.