BlockchainHub

MultiChain is a fork of Bitcoin, with changes making it easy to deploy arbitrary / private blockchains with custom configuration. Also see "this nice overview by Roderik": https://labs.kunstmaan.be/blog/hands-on-with-multichain

At the moment only binaries are available, but they promise to open source it soon.

"Instructions":http://www.multichain.com/getting-started/