Oh, absolutely! There’s lots of original work on tumblr, like areyoutryingtodeduceme’s comic Marked. You could also ask archiaart or lackadaisycats, both of whom do amazing work they post on tumblr and elsewhere.
If it’s m/m, you might try Shousetsu Bang Bang. (Although the sidebar description says “oneshots,” I’m fairly certain there’ve been multi-part stories as well.)
a paper mache bucket ... tumblr mirror 