I think you could add an option for docks how to behave when there is no screen to display on.
I don't use RDP -- can someone enlighten me about how apps see themselves when running in such a case?
The remote desktop tools i use don't change the host operating environment at all -- so all monitors are always there as far as any applications are concerned -- they don't know that anything has changed -- it's simply a case where the client that you use to connect looks at one monitor (or all) at a time.
But it sounds like with RDP its more like creating a new desktop, with only one monitor?