With a Raspberry Pi 3, some Linux knowledge and plenty of effort, Pierre Cuoy has created their own DIY DisplayLink
Raspberry Pi Adds Second HDMI Port to Laptop : Read more
Raspberry Pi Adds Second HDMI Port to Laptop : Read more
Sorry, just want to point out one more issue with poor Pierre's name. You've spelled it with a 'g' in one place "Gouy."Hello
Apologies, the corrections have now been made and the article should update in a few minutes time.
Great project and I love the process that you followed.
Best wishes!