> Is there anyone tackling this problem now?( or going to? )
> Otherwise, any hint would help me.

 I don't think anybody has tried to handle this. The problem I think
is that the mapping would have to be stored and if the hypervisor
doesn't support this maintaining this data in a coherent fashion
will be non-trivial. In any case the design for such a patch should
be discussed here first and with the openvz maintainers to make sure
the effort isn't wasted.

Openvz supports setting names for containers, see description on --name
parameter in vzctl(8). But you (or libvirt) actually need to specify
an unique container id anyway.