It would be really handy if we could pass in various bamboo parameters such as project key, plan key and build number to the script builder

Some variable substitution in the arguments list perhaps? e.g. ${bamboo.project.key} ${bamboo.plan.key} ${bamboo.build.number}

It may also be useful to have these set as system properties in the maven builders.

The uses for this may be many but the use case I am considering at the moment is to have web container port numbers generated by hashing these values together, automating the selection of ports for builds running on the same box.