You mention integration, functional, and acceptance tests, but then describe a plugin that only seems to address one. Would this plugin merely add one more set of tests for integration tests? It seems like it would be nice to have a plugin that could add additional tests of whatever name makes sense. An example of a tests DSL below.
tests {
intTest extendsFrom test
accTest extendsFrom test
otherTest extendsFrom intTest, accTest
}