I'm not a big IOC user so what I offer may not be applicable.
in my mvvm 'framework' my design time data (essentially view models) inherit from the run time view models.
I initially put them in the view project with the views - but I just had a quick try and moved the design time view models into their own project with their own namespace, changed the references in the views and bob was, as they say, my uncle.
I'd guess that using IOC this would be possible too assuming you can refer to a concrete class (the real VM) when you are dealing with the design time vm?
My articles are here
in case you want to have look to see what I'm talking about!