Most times it's a matter of economy of scale in terms of reprinting a ds poster. I've seen a few, but they are usually high dollar posters. While that version of Walk the Line commanded a few bucks early on, it's not enough to be reprinted I don't think. However, that was before Shepard Fairey was hugely famous, I think, so it may also be that there's more of a demand from that angle to warrant reprinting. In the end, I trust Mel's analysis.
H