Inter-VM scripting

Is there a possibility of inter-vm scripting?
Im talking about running a script in qubeA and that in turn changing the values and restarting a service in qubeB down the chain, is that possible or is it only possible to do this via dom0 qvm-run?

It depends on what you want to do, but you should be able to do it with Qrexec using policies and rpc scripts.