Here is a printer I am working on.  Based off the Prusa i3 I am using to print the parts with.  Uses V-slot extrusions for linear motion and has a lot of symmetry.

X carriage is wide enough for some imaginative tooling.  Whats your wish? 4 nozzle Kraken? rotary tool?  Bring it on, this printer was designed for multiple x axis configurations.  Want to try a dual extruder printer with seperate carriages for each extruder?  This printer is an excellent candidate :-)

This is a WIP and progress is slow since I am currently making the aluminum angle pieces on a cheap drill press.

UPDATE 4/23/15! Glad to say I've made a lot of progress....took longer than I wanted but all the mechanics are done! I am in the process of routing all the wires and installing controller board and power supplies. See the latest photo.   I am very pleased with how solid the mechanics feel, very rigid structure. There is no deflection in the linear guides for the bed since they are structural extrusions and are supported at either end as well as in the center....the smooth rods for the bed on my Prusa i3 have a lot of flex :-(

Also working on an enclosure for it that 'snaps' together in the T-slots of the frame.

I will update files for any printable parts I revised after it completes its first print :-)

Extruder is here https://youmagine.com/designs/geared-bowden-extruder--2