It isn't my longest project, but my current (game) project has the following stats. Only been going since about March, and I'm closing in on Alpha, so it's fairly concise (and lacking polish)
Total Physical Source Lines of Code (SLOC) = 4,970
Development Effort Estimate, Person-Years (Person-Months) = 1.08 (12.92)
Schedule Estimate, Years (Months) = 0.55 (6.61)
Estimated Average Number of Developers (Effort/Schedule) = 1.95
Total Estimated Cost to Develop = $ 145,484
(average salary = $56,286/year, overhead = 2.40).
Gotta say, personally I find lines of code much less important / useful as a measure when coding in C++. If anything, it's how everything fits together that's the "sticking point" rather than the length.
EDIT: That count doesn't include headers either, so it's purely implementation
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