I found this on Kickstarter and it's way too ingenious not to share:
https://www.kickstarter.com/projects/1661525705/z-unlimited-add-on-for-ultimaker/description
This guy took his Ultimaker, flipped it upside-down, and mounted everything but the build platform to a sliding door rail he had lying around. Here's a video of him printing a freakin' life-size elephant: http://youtu.be/nzwaVQaQgmI
These kinds of crazy ideas are why I love the current state of 3D printing :)