First of all, thanks to all of you who helped me in this process, who gave me feedback, who answer my questions, and so on. I'm really happy to be a part of the GSoC program, it's a great opportunity for me, and I'm glad I'm doing it with the help of this wonderful community. I want to remember you that the latest project examples can be found at: http://www.pcs.cnu.edu/~rcaton/ESUG/ESUG.html (I will upload some of these projects to the showcase eventually but IMO this should be the main site where to find my work) and the source code can be found at: http://www.squeaksource.com/GSoCSqueakland.html.
Well, it's time to work now :)
As Yoshiki suggested I made DataGraphMorph a kind of PasteUpMorph to allow the vectors and points to draw pen trace. But I ran into some problems. The main problem I have is that when I move across the plane the turtleTrailsForm doesn't update correctly. It also doesn't allow drawing beyond the extent of the morph. If I want to make the illusion of an infinite plane, the current implementation of the turtle trails should be modified (at least for my morph). What do you think?