I would recommend using something like this if you are wanting faster power cycle times than waiting for a "hands on" tech at the datacenter to get around to taking action on your ticket. I guess it all depends on your co-lo agreement.
http://www.digital-loggers.com/lpc.html
http://www.digital-loggers.com/lpc.html
That is pretty damn cool. It got me thinking too! I could easily set something like this up with my arduino
Right now I have my arduino sitting around collecting dust until Christmas time, when I use it to control 6 3-prong outlets for a Christmas light show. Would be easy enough to use it to remotely turn power on/off to my RPi.Parts list if anyone wants to manually make one of these:
Arduino: https://www.sparkfun.com/products/11021 $30
after searching a bit, ethernet shield here to control via web browser: https://www.sparkfun.com/products/9026
Control Relay: https://www.sparkfun.com/products/11042? $8
Any extension cord. $a few bucks
Tutorial: https://www.sparkfun.com/tutorials/119
Power arduino by my other computer sitting next to RPi, and if RPi ever turns off or freezes, remote into other computer, send command to turn relay off and back on. There is probably some way to code it to a web server too, I just don't have a clue. (Edit: check this out! http://www.hobbyist.co.nz/?q=web-switch-tutorial)