Anyone remember the Handheld Plastruder Mk4? http://www.thingiverse.com/thing:4156
Yes, but…but…kickstarter!
all of the gross weak wispy aspects of 3d printing with none of the automation!
For touchups I can see utility, though.
@Jasper_Janssen Also would produce very good-quality, smooth welds, although that’s not really a big issue.
and then you get http://www.kickstarter.com/projects/1351910088/3doodler-the-worlds-first-3d-printing-pen I’m surprised you dont seem to see in his video the power connection you’re going to need (I cant imagine batteries lasting long).
@Ian_Lewis1 I’ve seen battery powered soldering pens as well, a couple of AAs might go farther than you think.
also not "the first … " http://makibox.com/blogpost/items/makibox_smooth_print_public_demo_and_scribble
Whenever something says it’s “the first”, it usually isn’t. The plastruder mk4 hack is from 2010. donutman_2000 was such a visionary. 
Oh god, I even just ran across the “patent pending” bit on the 3Doodler