Expectations are indeed high that there will be a sea change in
India-Bangladesh relations following the elections. As for the maritime
boundary demarcation issue, the sticking point seems to be the methodology
being used for delimitation. Bangladesh favours the equity principle, while
India and Myanmar prefer the equidistance method as the basis of their
claims.
See, eg.(India-Bangladesh maritime talks inconclusive, Haroon Habib,
The Hindu, Sept 19, 2008:
http://www.hindu.com/2008/09/19/stories/2008091956481400.htm; also,
Bangladesh, Myanmar talks inconclusive, Nov 19, 2008:
http://www.hindu.com/2008/11/19/stories/2008111957071400.htm).
 
Have any such maritime boundary disputes been settled on the basis of the equity
principle, or is Bangladesh a precedent setting case?

On a more optimistic note, two recent articles advocate a more nuanced
position, arguing that India should take a diplomatic rather than political approach to the delimitation issue:

India-Bangladesh Maritime Dispute in the  Bay of Bengal
The New Horizon, Dec.26, 2008 - Diganta
http://horizonspeaks.wordpress.com/2008/12/26/the-maritime-dispute-with-bangladesh

Indo-Bangladesh Maritime Border Dispute: Problems and Prospects
Dr. Alok Kumar Gupta, Assistant Professor, National Law University, Jodhpur
IPCS: Institute of Peace and Conflict Studies, Article no. 2699, 8 Oct 2008
www.ipcs.org/whatsNewArticle11jsp?action=showView&KValue=2715&status=article&mod=b

Dr Gupta makes a cogent point regarding the principle of fairness and justice which is outlined below:

The resolution of the maritime border dispute between India and Bangladesh
is of utmost importance and should be done in accordance with international
law and agreements between the two sides. India's stand is that the solution
should be based on "equidistant principle" whereas Bangladesh's claim is
that it should be resolved on "equity principle" meaning that the countries
adjacent to the Bay of Bengal would get proportional areas in the zone.
The Bay of Bengal is located to the south of the land territory of
Bangladesh which is in a rectangular domain and that gives Bangladesh the
right to claim marine areas in a rectangular orientation extending 200
nautical miles to the south in the Bay from the extremities of its land
territory. The fact remains that the delimitation of sea boundary between
two lateral or adjacent states, such as Bangladesh and India, is different
from that of opposite states such as India and Sri Lanka or Australia and
Indonesia.
The method of delimitation (equidistant method) between two opposite states
may not apply between adjacent states because it grossly distorts the
boundary, contrary to the principle of fairness and justice (equity
principle). Therefore, any attempt towards maritime border conflict
resolution should take into account a few key factors. Prior to the
demarcation of the sea boundary, the border of the Haribhanga river is
required to be determined first. Ordinarily, in the case of a navigable
river, under international law (Article 76 and 82 of the UNCLOS), the
boundary line runs through the middle of the deepest navigable channel
(Thalweg principle) unless agreed otherwise between the parties. Also,
according to international law, the states shall settle the boundary through
negotiations. If negotiations fail, the principle of equity will apply,
implying that justice and fairness must be the hallmark of the settlement.
There should be a joint Bangladesh-India marine survey on the Haribhanga
River to determine the exact position of deep-water navigable channel or the
main channel of the river. India has so far, been reluctant for a joint
survey, which is wrong, given the big brother-small brother syndrome that
India's neighbors suffer from. A joint survey will mitigate many of the
disputed claims and counter-claims over the entire issue. Both countries
should try to involve a neutral third party or if agreed may refer it to an
international tribunal. However, India would perhaps be reluctant because of
its experience in the case of Rann of Kutch, but this is not to say that
things will turn out the same way again.

Regards,

Dr. Jayita Ray
Flinders University
Adelaide, Australia