I don't know of any Bluebook style, and I think I would if it existed. Given the notorious complexities of the Bluebook it would have to be a biblatex project, and it would be quite a project! In the common law world, I know there is a written-and-working-but-unreleased version of the McGill style for Canadian authorities, there's a partially compete Australian style, and there's an English style based on OSCOLA, which is on CTAN. None of them is Bluebook conformant. The one that I think is closest to complete (which is OSCOLA -- but (disclaimer!) I wrote it so I suffer parental bias) might provide a start -- but it would only be a sort of "inspiration" start, rather than a "much of the legwork is done" start: also it's hardly a stable package.
Implementation of a subset of the Bluebook (say books, articles, cases and perhaps the Constitution and USC) wouldn't probably be too much of a struggle. Implementing the whole thing would be a mammoth task. How mammoth would depend on how far you sought to automate things like abbreviations, cite signals, citation order and the like.