Sure, with a suitable video setup DPMS is a must.
Some years ago when I used AGA and a scandoubler, I wanted to use DPMS but one software would do it poorly, crashing, others wouldn't do it at all for AGA. So I mostly used a black screen that would appear after first dimming the screen quite a bit. The joys of palette manipulation. :-)
I wonder if there is there a way to do this for any screenmode on all the ATI Radeon cards, some gamma register? But since it's not what it is meant to do, it may not be that flexible. Would be a good way to remind a half-conscious/otherwise lame person to "hit any key" so that the screen doesn't sleep first.