No, there is no known date yet.
However, and regrettably, FHQ omitted the Maine Republican caucuses from our primer on when the last few undecided states set dates for their 2012 presidential delegate allocation.1 Instead of adding it quietly to the primer, we will give Maine its own spot and also add it to the primer.
Maine: Like many of the other Republican caucus states, the date of the Maine GOP caucus meetings is to be determined. Also like many other Republican caucus states, it is informative to look at the state party rules for some indication of the procedure by which the date of the municipal caucuses are set. According to the 2010 Rules -- those governing the 2012 Maine Republican convention -- the party has to, based on state law, hold a state convention between March 1 and August 1. Beyond that guideline outside of the state party's control, Rule 7 of the Maine Republican Party's rules further describes the guidelines imposed on the party's State Committee -- the entity charged with setting the municipal caucuses date(s). Rule 7 states that municipal caucuses will be held every two years according to state law and "upon [the] call of the Chairman of the Republican State Committee". In addition, Rule 7b encourages municipalities "to conduct their caucuses by March 1 or a single date if so specified by the State Committee". That gives us some idea of a window of time in which the Maine GOP may hold caucuses. If 2008 is a precedent -- and there is not necessarily a reason to believe it is -- the Maine Republican Party will seek to hold Sunday caucuses. In 2008, that was on the Sunday immediately prior to Super Tuesday. The Sunday just prior to the earliest date states are allowed by the national parties in 2012 -- a date FHQ will reluctantly call Super Tuesday -- is March 4. That obviously falls after the rules-encouraged pre-March 1 guideline. The Sunday prior to that is February 26. The Maine Republican caucuses are likely to fall into a window that begins with Sunday, February 26 and ends on, coincidentally enough, Sunday, March 11, the date on which the Maine Democratic Party caucuses are scheduled and the Sunday immediately following Super Tuesday.
Best guess on timeframe for a decision: According to the Maine Republican Party rules, the State Committee meets monthly. The party will, therefore, have a couple of opportunities -- in August and September -- to decide on a date prior to the RNC's October 1 deadline by which dates are supposed to be set.Threat level: Low. Maine was quietly non-compliant in 2008 and if the Republican Party chooses to repeat similar scheduling of their caucuses in 2012, will likely see a similar level of attention (mainly because if the contest immediately precedes Super Tuesday, candidates will be focused elsewhere).
1 At the last minute, mid-draft of the primer, I realized that I needed to include Minnesota and in the process -- I was writing alphabetically by state -- left Maine out.