In 2011 there were about 500K utility patent applications: http://www.uspto.gov/web/offices/ac/ido/oeip/taf/us_stat.htm Many of those are not software related.
There are about 1.3M programmers in the US alone: http://programmers.stackexchange.com/questions/19720/where-c...
So 20 teacups each to have each patent looked over 10 times? Sounds doable to me.
So maybe 200 teacups each but the direction is definitely right.
I'm not doing anything close to as good a job as a patent examiner would do, but with about an hour of work I (hopefully) was able to start pointing to some prior art that could get an examiner quickly up to speed on what the state of the art is.
I agree the amount of work involved to comprehensively invalidate a patent would be days - hopefully a group can do the same with shorter time contributions.