Emma, C. Hessami, R.M. Larsen, K. Marinelli, A. Robles, R. JACoW Publishing Geneva, Switzerland Plasma-driven light source development has recently made significant progress with the demonstration of plasma-FEL gain and the work of multiple facilities towards plasma-FEL development *. In this paper, we report on the status and prospects for one-such plasma-driven light source effort, the Plasma-driven Attosecond X-ray (PAX) experiment at FACET-II ** . This unique experimental thrust seeks to generate 100-attosecond long electron beams using plasma accelerators and use these beams as drivers for an attosecond X-ray source. This approach is motivated by the possibility to generate ultra-short high power attosecond X-ray pulses, as well as the order-of-magnitude increased tolerances of this method to emittance, energy spread and pointing jitter compared to a plasma-driven XFEL starting from noise. We present recent experimental developments in the process of demonstrating this concept at FACET-II and discuss potential extensions of this method to scale towards shorter wavelengths in the future.