I'm sure you'll be thrilled to know that my Scratch Pad app is now available in the Marketplace. More important than creating a custom cut and paste implementation, this proves that it's possible to store data on the device and share it between applications.
In time, I'll explain how I did this. And, also, why you, probably shouldn't!
Until then please feel free to tweet about my app and be sure to use the hashcode #wp7comp or post your comments here.