Just my 2 cents, but they do work.
At GeekLayer we use them for fast setup, of course though, we have to go in and change the settings to the correct IP 'Main Shared Virt IP', but none-the-less it does work.
The cpanel license is bought ahead of time before we actually start the creation though, that way when the VPS is setup everything works a-OK.
Edit: Of course, Daniel has already said this, it's just a matter of you trying yourself.
HyperVM has a 'create OSTemplate' which images everything of the current server, cpanel/whm included. When you setup the new VPS you select that template and within an hour or so, it's setup.