I'm modify the tantillus case to hold 20cm*20cm*20cm print volume , hope you like it.
I've uploaded to the lasercut case to [www.thingiverse.com]
The tantillus a2 printer has a limited build volume (10cm 10cm 10cm) , so I build a version named tantillus a3 (16cm 16cm 16cm ) , this one make tantillus a3 even large , it has build volume of 20cm 20cm 20cm, which can install a popular heated bed (20cm)
Get your corner connectors from tantillus a3 (http://www.thingiverse.com/thing:1520640), for all other components , download from tantillus a2 (http://www.thingiverse.com/thing:480860), they can be reused in a4 version, (x y robs , carriage robs and z screw thread need to be in different length although).
A notice, this is still in progressing , the main problem is as following:
The old z arm may not support the large heave z bed, z arm should be redesigned.
The extruder is far away from the carriage , this makes retraction a problem , I'm consider make extruder more close to the carriage.
Printed Parts List: