Tuxedo InfinityBook Pro
I was looking notebooks and stumbled across Tuxedo. What do you think about InfinityBook? It's a 13inch notebook with quadcore option. I already asked them about the lanes on the Thunderbolt port but still waiting for an answer.
EDIT: Support confirmed that 4 lanes are available.
As far as I know this notebook is based on Clevo N130BU and N130WU models. You can check review here. There are also other notebooks based on this Clevo model, like System76 Galago Pro (there are a lot of reviews of this model).
At some point of time I was checking if this notebook is a good choice for me, but I found multiple reviews saying that it is quite loud. I think I also found that it lacks power delivery through Thunderbolt port (but you may want to double check it).
If you don't mind those disadvantages, then this is a very good notebook in my opinion.