As the saying goes, version 1.0 always has bugs, and ReAssure was no exception.  Version 1.01 is a bug-fix release for broken links and the like;  there were no security issues.  Download the source code in Ruby here, or try it there.  ReAssure is the virtualization (VMware and UML) experimental testbed built for containment and networking security experiments.  There are two computers for creating and updating images, and of course you can use VMware appliances.  The other 19 computers are hooked to a Gbit switch configured on-the-fly according to the network topology you specified, with images being transfered, setup and started automatically.  Remote access is through ssh for the host OS, and through NX (think VNC) or the VMware console for the guest OS.