Considering NCD: you might have noticed that NCD was never meant to be a general-purpose language, but rather a simple scripting language for controlling other programs and OS configuration. My thinking was that extending a language with the features that define NCD (asynchronous execution, backtracking and extended statement lifetime) would essentially require a complete rewrite of a language implementation. However after seeing tamejs and your CPC I'm not so sure anymore :)
P.S. Check out the Read File example I just added to the NCD demo page; it shows how backtracking can be used to handle errors elegantly.