@psantori 

Hi, 

Currently, there isn't another model which support establish Powerline Mesh with Deco PX50.

Deco P7/P9 also supports powerline Mesh but they use another powerline standard-HomePlug AV2 while Deco PX50 is G.hn. If you need an extra Deco, you might need to purchase another Deco PX50.

As for the second request, "can you suggest an additional model to extend the powerline network in a standard (non router-connected) fashion", what do you mean "non router-connected" precisely, like the powerline adapters here?

https://www.tp-link.com/en/powerline/

Thank you very much and best regards.