Discord user Gistix in the Flat2VR discord server has ported the L4D2VR mod to Portal 2. While it's not an official team project, it is Source and it is VR so it seems interesting enough to post about. It is still in the prototype phase and is not publicly available yet.
(Edited)
5
4
That looks immensely nauseating.
portal 1 vr would be cool