Have you ever seen a Gibson TGE05 Echoplex Digital Pro Plus? These are remakes of the originals that Eddie Van Halen used to use in the late 70s. Pretty sure that he used it on the recording of Eruption for some of the Delay parts. There are very expensive but wow. Do a search for one. Echoplex is an enormously powerful 19" rack mountable effects unit that encompasses digital recording, sampling and digital delay. With a total of 198 seconds of memory time on-board (16mb), the capability to layer up to nine loops at once, Tap Tempo and a host of other features, the Echoplex is limited only by imagination. As a live performance tool for the creative instrumentalist, or a ingenious device in the studio, the Echoplex opens up all manner of sonic opportunities, allowing you to explore ambient soundscapes, reversed loops and rhythmic drones to your heart's content.
It is a professional effect that might be a little to much for some. But once you use on you'll never leave home without it.