From what i gather about mark's request, he wants to see the linework as unbutchered as possible because within this one can glean some information about the thinking an artist puts into his/her work.
the best opportunity is to seet he lineart itself in the flesh as one can see all the little tricks an artist has used to create effects. merely scanning and isolating the black lines in photoshop wouldn't really do this, as any subtlety in line would be lost in the process.
what you would end up with is an apporximation of the line, kinda like original art which has been photocopied 20 or so times.
Anyway, there's plenty of pencil/line art in the artwork section!!
Fraston