X-ray interferometry has the potential to provide imaging at ultra high angular resolutions of 100 micro arc seconds or better. However, designing a practical interferometer which fits within a reasonable envelope and that has sufficient collecting area to deliver such a performance is a challenge. A simple system which can be built using current X-ray optics capabilities and existing detector technology is described. The complete instrument would be ~20 m long and ~2 m in diameter. Simulations demonstrate that it has the sensitivity to provide high quality X-ray interferometric imaging of a large number of available targets.