Ask HH: Does this app exist? (robust virtual scratch paper)

I'm looking for the best of two worlds: sketching thoughts on paper and typing, but I'm not talking about an iPad app. I'm talking about something for use with a full keyboard and a mouse.

1) I love to scratch out thoughts on paper while rotating the orientation so that multiple thoughts are all in one place but distinguished by their orientation.

2) At the same time, I also love the convenience of typing on my keyboard.

The key benefits are:

* Able to organize and visualize many thoughts in close proximity without wasted screen space

* Convenient to the workflow of laptop users (ie. no paper, fast typing)

* Liberating -- no imposed structure, no pressure to do something clean, easy to trash

* Fast

* Fun/attractive/natural

I'll describe my deal app to give an idea of what I'm looking for (and because it's fun to conceptualize apps).

As I see it, the salient features would be:

* Able to change text size very quickly (i.e. mouse scroll wheel)

* Able to rotate paper very quickly and smoothly to any degree while the text is maintained

* Able to rotate cursor orientation very quickly and smoothly up to 45 degrees above or below the horizontal

* Super-easy to shift into low-res drawing mode (bonus points if jankety mouse movements are averaged into something that looks like a confident stroke with a pen/pencil - this doesn't need shape and line and curve tools etc, just render what the mouse traces)

* Easy to strike through text (not via formatting, via a slightly different drawing tool -- I imagine you pick the strike out tool, select the area, get a zoom in, and then use the normal drawing mechanism only at the more granular level)

* crumple up the sheet of paper in a really satisfying way to get a new sheet

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In short, it's a more robust facsimile of virtual pen and paper.

I would love an app like this for thinking, but I would use it just as much as a teaching/communicating aid.

Does this or something with similar functionality exist?

If not, how hard would it be for the right person to build? (just out of curiosity)