What you are looking for is "linear power supply" as opposed to "switch mode power supply". Might help in a search. Commercially, the kind of thing you are looking for is "PS806-12 Linear power supply" from Zapp. I'm sure that you could build one for less, as already suggested, but the Zapp supply is the kind of specification that you need. I'm currently running an MDF router with one of these supplies, three SY60 motors, and M752 drivers. These drivers are old analogue boxes, now superseded by things like the AM882, but the combination is fine for this class of machine. The MDF structure can't take much more power anyway!