There's a company that have/are developing a very parallel computer called Parallella. It looks like it has lots of potential, but it runs some C style language.
Q. Has anyone written a language specifically to take advantage of massively parallel computers like this?
There are a definitely languages that have been designed to deal with the rising popularity of parallel computing. Parallel processors have sky rocketed in popularity since the death of Moore's Law. Support for better parallel computing in programming languages has followed quickly in its path.
My personal recommendation would be either Haskell or Clojure. Both are functional languages which have made great strides in parallel and concurrent computing leveraging their functional nature to gain advantages. Haskell has a really nice book called Parallel and Concurrent Programming in Haskell by Simon Marlow. I've read it and it's excellent. Clojure has also been built from the ground up with concurrency in mind. An interesting new player in this space is Julia, but I can't say I know much about it at all.
As for clause 1, I don't know what a managed language means. EDIT: What you're calling a managed language is more commonly called garbage collected language. You might want to use that term to help get more effective answers. Also all the languages I recommended have garbage collection.
As for clause 2, Haskell definitely makes parallel computing fairly automatic without any worrying about low level concepts or locking. There is a simple function called 'par' which allows the programmer to annotate two computations to be executed in parallel. The semantics guarantee that the expressions be evaluated when they're necessary and since the computations are functional they are guaranteed not to interact in non-thread-safe ways.
As for clause 3, you're on the right track to be looking for a functional language. Functional subcomputations have automatic thread safety which pays big dividends when it comes to ensuring parallel execution doesn't cause problems. It can't cause any if the computations are functional.
As for clause 4, good luck finding a functional language that doesn't have lambda ;) EDIT: It's not, strictly speaking, part of the definition of a functional language because there is no formal definition for what a functional programing language is. Informally I think a lot of people would mention it as one of the most important features. Concatenative languages or languages that are based on tacit programming (aka point-free style) can be functional and get away with not having lambda. I wouldn't be surprised if the K language didn't have lambda despite being functional. Also, I know for sure combinatory logic (which is the basis for K) does not have lambda. Though combinatory logic is just a theoretical basis and not a practical programming language.