You can do all of those things right now. StrataFrame will not be based in 3.5 for a while as this would push a lot of developers towards a schedule that they would not want to keep. As for WPF and WorkFlow, we have developers using these tools as we speak. I will tell you, though, that if you plan to use WPF for a data applicaiton, you will be very disappointed with the results. WPF is horrible for data entry based applications. If you are going to have an application that is geared heavily towards graphics and rendering, then I would recommend WPF. So in short, there is actually very little demand for WPF in data applications at the moment and there are more important things on the radar.
Long term StrataFrame will provide a WPF collection, but due to a serious lack of demand and the limitations of WPF on the data application side of things, it will probably be 2.0 before any major consideration goes into a WPF collection.
Now, if you want to use WPF using the standard .NET controls or another UI control company, then you can already do that as we speak. .NET 3.5 is built on top of .NET 2.0, so you can use workflows, WPF, etc. if you so choose.