Thank you! I'm actually working on my own synchronous language, but it's more in line with Lustre than Esterel. Synchronous dataflow with soft real-time goals. If it starts to look like something decent I'll put it on github.

Since you're interested in the implementation of synchronous languages you could also take a look at Quartz [1]. Their book is a fantastic resource about the topic.

[1] http://www.averest.org