There is no need to create a POCO mapping of a DataSet that is a member variable within a ViewModel, is there?
If the DAL hands you a ready made datatype, be it ADO Entity or a DataSet, why not use it in the ViewModel?
The ViewModel is, among other things, a land of normalizing data for UI consumption, so you can resurface the DataSet as a property from the ViewModel and bind the UI directly to it. Regardless of any protests, you've insured proper seperation of concerns
of UI and non-UI. If there is some business logic to perform on the data within the DataSet, you have it in your ViewModel read for processing...
Prism does have major plumbing ready to use, but sometimes it is also overkill for smaller applications. It is for composite applications, like those sporting plug-in architecture and painless deployment.
I would not hesitate to use a ViewModel class for the most mundane and small applications for the purpose of building a good habit as well as adding quality to your code via unit testing and re-use portablility.
I've looked at the code for the infamous Josh Smith artice in MSDN magazine and am having trouble seeing how a Dataset could be worked into the ViewModel.
Is there a good example out there that ties a Dataset with the MVVM pattern?
I took a quick look at NHibernate, but I'd rather stick with libraries that are part of the Framework, at least until I get a handle on MVVM.