An alleged test pressing of Aphex Twin’s unreleased Caustic Window album is on Discogs for $13,500 – FACT Magazine: Music News, New Music.
I remember seeing this pop in my wanted list on discogs. I nearly shat myself, but I'm not involved in the WATMM community because I suck at keeping a consistent online presence. I liked Caustic Window, but not nearly as much as his AFX handle. As far as output goes, the quality of each pseudonym for me is AFX > Aphex Twin > The Tuss > Caustic Window > Polygon Window > Power Pill.