GitMiner
Pet project I built to experiment with different concepts.
GitMiner allow "mining" of vanity Git SHA1 prefixes.
The HEAD commit is altered via variations over committer and author timestamp adjustments. Other commit metadata such as commit message or description are left as their original.
Installation
These options will add the git-mine binary which act as a Git custom command: git mine.
Rubygem
gem 'git_miner'
Manual
gem build git_miner.gemspec
gem install --local git_miner-*.gem 
Usage
git mine [DESIRED_PREFIX] will amend the current HEAD commit with a new mined SHA.
Eg.:
git mine c0ffee
Some extra options are available (experimental):
$ git mine -h
Usage: git mine [options]
        --engine [ruby|c]            Set the engine (default: ruby)
        --dispatch [simple|parallel] Set the dispatch (default: parallel)
        --verbose                    Run verbosely (default: false)
        --register [prefix]          Register automated post commit git hook
    -v, --version                    Returns the current version
    -h, --help                       Show this message
Development
[path]/git_miner/bin/git-mine ...