Luc,
I just spoke with someone very knowledgable of SRM and he said we don't have any built in way for doing it with powered off VMs.
That being said, you could use a tool like the VDDK to edit the files of an offline VM, which you could use to change Linux IP addresses, and I believe they are also going to add the ability to do this with offline registry hives at some point, which would cover Windows.
Obviously this would be rather ugly, but if anyone goes down this route, please let us all know.