More than one Stream per Model?

[nerdoc]

Could turbo be refactored to add more than one Stream per Model?
It sometimes is needed to add more streams to a model to add different functionality (of different plugins e.g.). If there is already a model stream, it "blocks" adding another one.
So plugin functionality has to be added into the ModelStream.

This IMHO could be done better by making it possible to add more than one Stream to a Model, and e.g. making .stream a list object.

Is this possible?