A few hundred? Hundred thousand, maybe. Here are several sites where volunteers run computer chess tournaments 24x7 and publish the resultant rating lists.

http://www.husvankempen.de/nunn/ http://www.computerchess.org.uk/ccrl/4040/ http://ssdf.bosjo.net/list.htm

There are more but these are the reliable and longest running that I know of.

This is already a thing - see http://en.wikipedia.org/wiki/World_Computer_Chess_Championsh...

It's enough of a thing that there was drama and accusations of cheating/plagiarism a few years back http://en.wikipedia.org/wiki/Rybka#WCCC_disqualification_and...