Hi there,
This could be of interest as well: http://robotwebtools.org/
The main drawback is that it seems to rely on ROS, but relying on Pypot instead is probably possible.
Btw, an interesting alternative of ROS that I’m currently using is YARP (the middleware used by the iCub community). Its main advantage compared to ROS is to be very light (can run on an Android smartphone), quite simple to install and cross-platform. It could be of interest as the core of a visual programming tool “a la Scratch”, to manage communication between modules. (I haven’t found a topic about visual programming so I put it here, let me know if there is a better place I’ll move it).
Cheers