has this method of collection been tried before? if not I'm guessing this is an untapped goldmine for the right entrepreneur: set up charities with simpler donation vectors.
Wikipedia has the basics of setting up a new short code: "Common short codes in the U.S. are administered by NeuStar, under a deal with Common Short Code Administration - CTIA. Short codes can be leased at the rate of $1000 a month for a selected code or $500 for a random code." (from http://en.wikipedia.org/wiki/Short_code)
More info here: http://www.mmaglobal.com/shortcodeprimer.pdf