"Heartbreak through drawing" elaboration

I have been trying to come up with a few more initial ideas to give myself a wider choice and an array of possibilities for production, however, I have just ended up elaborating on my first idea - "heartbreak through drawing". To expand on my idea I have become more specific in what I could potentially do. Effectively, I want to create moving images from "sketched ones".

My idea was for the character to be filmed, through a combination of over-the-shoulder shots and ariel view shots, drawing scenes that he remembers from his "not-quite-a-relationship" with a girl in the past. After he draws something to do with the memory (e.g the girl riding her bike towards him), the picture then "comes to life" and the scene is played. Each scene/memory ends with a negative shot, a moment that the drawer remembers to have been negative and vital in reason for the girl and himself to depart (e.g. the girl looking at him with tears in her eyes). This would then turn in to a sketch, ending the scene. This same process would happen for each memory, the boy drawing the start and ending of each. After a few memories, the ending will climax, and the boy would erase the ending that he has drawn (the true ending), in order to redraw his dream ending (the false ending). This is the boys way of showing "what he should have done". This "false scene" would end the same as the others, with a final sketch. At this point the boy would look up from his paper to see the girl, who happens to be his neighbour, out of the window, walking out her door holding hands with her now-boyfriend.

To break this down a little..

So how would this work technically?

The entire sequence would be filmed first, prior to any drawings. Screen shots would then be taken of the first and last shot of each sequence/memory (in order for the sketcher to copy). The drawer would then be filmed sketching the basic outline of this shot (which would be sped up during editing) and as he finishes this will be cut to the actual shot to look as though it has changed into a real image. The last shot of each memory will be drawn before hand ready to be cut to after the end of the sequence, as though the drawer has drawn the whole thing (really just the first and second shot). Imagine below is the sketch with its scene, the sketched bike would cut to the filmed shot which would then continue into its sequence...
(sketch would be of better quality if this idea was persued, I am not an artist!)

A sketch cutting to a filmed shot  

Potential problems?

Well, there are definitely a few flaws with such a complex narrative/idea but I feel that these could hopefully be resolved. I would need to make sure...

• The drawings were clear enough so that the camera can pick them up - the drawer would need to press down hard on the paper. I have hold of a 9B pencil which draws with thick lines
• The lighting is professional as paper and pencil marks can look dark - I have access to a "sunlamp" which emitts the equivalent light to sunlight, so natural light should be maintained well for both the filmed scenes and the drawings

Although this seems a complex idea, I feel that if I spend enough time on it I could end up with a really great, effective looking short film so I am definitely ready to be challenged if this is the case!