I see no use for vagrant in proxmox due to the following reasons:
1) Vagrant is more or less providing a subset of proxmox
2) Vagrant is designed to provide desktop VMs while proxmox, as vmware et al, is designed to provide server VMs
3) Vagrant lacks, IMHO, all the building blocks which constitutes an enterprise solution.
knife proxmox server create --hostname new.webserver.com -r "role[name_of_role_for_your_new_webserver]"
Not should be, it is!I agree that vagrant-proxmox should be useful.