Where do homeless people vote?

So here's an issue: when election day rolls around I will be essentially homeless (in the sense of no fixed address). I will probably be somewhere on the ICW in North Carolina, hundreds of miles from the town where I've been living (and voting) for the last 5 years. Many less fortunate people are homeless in the very real sense of the word - living on the street or in shelters.

It's always been my experience that you have to produce some kind of id to vote: state-issued, passport, electric bill with photo id, etc. That supposedly proves you have the right to vote in the election because you are in your home district, precinct, or whatever.

It's an artifact of our outdated electoral system that a US citizen can't vote in a national election from any polling place - since really you are voting for electors they (the federal government) can't allow anybody to vote from anywhere - imagine what 10,000 voters from a liberal northeastern state (all safely democratic - would not miss 10,000 votes) voting in Ohio in '04 would have done...

Kind of a conundrum. My choices as I see them are:

1. Cast an absentee ballot in a state in which I no longer reside

2. Don't vote

I really don't like either one. If we would wake up and use the popular vote to determine the election results then it wouldn't matter where I was when I voted...