My book DSLs in Action (see sidebar) is now available in MEAP (Manning Early Access Program). I have planned it to be one totally for the real world DSL implementers. It starts with a slow paced introduction to abstraction design, discusses principles for well-designed abstractions and then makes a deep dive to the world of DSL based development.
The first part of the book focuses on usage of DSLs in the real world and how you would go about setting up your DSL based development environment. The second part is focused entirely on implementation techniques, patterns and idioms and how they map to the various features offered by today's programming languages. The book is heavily biased towards the JVM. The three most discussed languages are Scala, Ruby and Groovy, with some snippets of Clojure as well.
The book is still very much a WIP. Please send all of your feedbacks in the Author's Forum. It can only make the quality better.