There have been quite a few metal covers of Rainbow Factory, but none of them were really as intense as I'd hoped, especially considering the Rainbow Factory is the most metal song in existence that isn't actually metal.
So I grabbed my axe, kicked the tempo up to 180 BPM, and started shredding. I threw in part of Incarnated Solvent Abuse by Carcass to make things interesting, and this is the result: ridiculous amounts of metal.
http://soundcloud.com/matt-kaltenwinter/incarnated-rainbow-abuse-metal
It's a bit rough around the edges, but hey, it's metal! Featuring ponies! And a tribute to two of my favourite musicians, WoodenToaster and Carcass.