I recently converted a Dell EPS-470 (I bought two of them from ebay for $17.50 each shipped). It is a 47V @ 9.6 amp supply, and I have it connected to a DPS5015 buck converter. This provides control of the voltage and current. Works great, but I have the Dell PSU connected to a power strip with a switch for powering it up and down (the DPS pulls a high spike at power up so they recommend making all power connections and then powering up the input PSU (the Dell in my case).
It is a bit noisy, but I disabled two of the 3 internal fans in the Dell and that toned it down a fair amount. I am not driving it hard at all, so I am not too worried about the heat. The DPS5015 purpose-built enclosure has an always on fan, and that is louder than the Dell supply now.
The form factor of the Dell supply is nice since I can stack stuff on top of it (my new-to-me Agilent E3646 is on top of the Dell supply in the attached image, and the DPS is the small box with the color screen on the shelf). The second image is of the back, showing the binding posts I added to the back of the enclosure.