'Case-less' Rackmounts and Multi-Machine Power Supplies?

phungus asks: "I'm looking for manufacturers of rack-mounted 'case-less' system trays for a project I'm researching. I'd like to rack-mount all of our dedicated servers without using cases. Ideally, you could put all of the components on one tray. I'd also like to find out if anyone knows of manufacturers who make big multiple-machine power supplies (ATX) so that I can eliminate individuals from the picture. I seem to recall an advertisement in a Linux magazine that did exactly this but can't seem to find it anymore. It would be nice if it supported standard relay racks, but full-enclosures would be okay too."