It's now possible with grails a few grails 2.3.6 libraries :
@Grab("org.grails:grails-datastore-gorm-hibernate4:3.0.0.RELEASE")
@Grab("org.grails:grails-spring:2.3.6")
@Grab("com.h2database:h2:1.3.164")
...
The rest of the example is here : https://gist.github.com/graemerocher/c25ec929d9bcd1adcbea