There are several ways to create SketchFlow prototypes. You can draw sketches, scan them, import to Expression Design/Adobe Photoshop, make some fixes, import separate pieces to Expression Blend, create animation and so on. This way is beautiful, creative but too long. Another way allows you to create functional prototype directly in Expression Blend by using default sketch styles and sample data. You can get a real prototype with sketch styles but with real images.

So it would be nice to create a third edition. Take real pictures, illustrations, photos and add sketch effects. Why not? You can create these effects and apply to different collections: people, auto, furniture.

Take a look at these examples I made in Expression Design for ReMIX10:  

Original:

With effects:

So you can get such SketchFlow prototypes with sketch images:

You can copy effects by using Attribute Dropper . That tool copies the effect from an existing object to another object.

The best combination is Poster Edges + Note Paper  or  CrossHatch + Note Paper. Hope you like it too:). 
Enjoy -> Expression Design Sketch Effects.