Here is a lucene2seq tool I used in a project. It creates sequence files based on the stored fields of a lucene index.
The output from this tool can be then fed into seq2sparse and from there you can do text clustering.
Comes with Java bean configuration.
Let me know what you think. Some CLI code can be added later on. I used this for a small-scale project +- 100.000 docs. Is a MR version useful or is that overkill?
See https://github.com/frankscholten/mahout/tree/lucene2seq for commits and review comments from Simon Willnauer (Thanks Simon!)
or the attached patch.