There are many examples of using VPP with tap interfaces/namespaces. After reviewing these, and details at https://wiki.fd.io/view/VPP/Tutorial_Routing_and_Switching, we came up with the following setup for testing inter-VM connectivity using VPP's vhost-user.
Grab VPP packages, per directions from FD.io at https://wiki.fd.io/view/VPP/Installing_VPP_binaries_from_packages
$ sudo rm /etc/apt/sources.list.d/99fd.io.list
$ echo "deb [trusted=yes] https://nexus.fd.io/content/repositories/fd.io.ubuntu.xenial.main/ ./" | sudo tee -a /etc/apt/sources.list.d/99fd.io.list