Linear PSUs are the choice because you don´t have to deal with RF dirt inside your cases. Our member silent:arts sells PSU PCBs, have a look into the Schwarzmarkt section.
Power one supplies have been used in Amek desks. They are now called bel power solutions, see here: http://www.mouser.de/bel-power/product-line/ IIRC Hypex offer some PSU and regulator boards.