I think it's possible because of a few reasons:
1) Typically low turnout in special elections
2) Republicans vote in higher percentages during special elections
3) Since there is so much anti-health care, anti-cap and trade, anti-socialism rhetoric, more Republicans will vote
Can you imagine if a Republican wins in MA? It would make world headlines.
Unfortunately, living in MA, the newspapers have been essentially silent. And if not, most every article about the election, while attempting to be non-biased, shows only a picture of Coakley.
If a Republican won, it would be such a breath of fresh air only because the Independents (me) and Republicans would actually feel as though their Presidential votes may actually matter. It would change the entire political landscape.