The Mendel90 is being updated to include a new bowden-type extruder. I have done two test print revisions, and the latest should be done by Feb 16, 2014. Once these designs are adequate, they will be shared on the Mendel90 page.
The Mendel will also receive a dual-head upgrade, presuming the electronics are up to the task, since the bowden extruder will free up some space on the carriage.
Gingery Metal Shop
Though a bit of a stretch goal, I'd like to eventually build the Dave Gingery "Metalworking Shop from Scrap".