Hi,
I don't know of any other implementations.
Is is possible to get libcsp working without a threading model. The only function requiring regular calls is the router. This normally runs inside a task but could also be called from a normal main loop.
The biggest issue as far as I am concerned is the need for queues. in particular on blocking calls. Both csp send and receive can be non blocking. So I think it can be implemented with a polling service instead of blocking.
If you wish to experiment with this. I will be happy to assist you. I know of several others that is interested in this feature as well.
Regards.
Johan.