I have to agree with Matt you guys are making this too complicated. Keep in mind guys raffles are for people who can't do math.
At some point you just need to draw a line in the sand and say you are doing it this way whatever that way may be and if people don't like it then they don't participate.
Yes I did buy a couple tickets but I think the current method is more then fair.
Oh and I know many people who use random.org and just stream the pick on ustream or justin tv.