No state currently accepts Bitcoin directly as payment for taxes. However, it's clear that the idea is garnering some interest. In addition to New Hampshire, the state of Utah (maybe not-so-coincidentally the home of Overstock.com) is exploring the idea. This year, Utah State Representative Marc K. Roberts (R), introduced H.C.R. 6, Substitute Concurrent Resolution on Payment Options for State Services which proposes the creation of a Council on Payment Options for State Services to study whether and how the state could accept Bitcoin as a valid form of payment. Included in the list of potential services, via the Office of the State Treasurer and the State Tax Commission, would be the payment of taxes.
For now, most of these ideas are still exploratory - but not so far-fetched. In a recent poll for The Wall Street Journals MoneyBeat blog, a whopping 83% of respondents indicated there is a future for cryptocurrencies such as Bitcoin. Whether that future includes a payment option for your taxes remains to be seen.