TK300 by RockyShi is on Thingiverse now ... information may be limited, design looks sturdy, it is made with steel side plates and CNC aluminum connecting parts ...
From Thingiverse description:
Dual extruder version:
http://www.thingiverse.com/thing:212131
Base version:
http://www.thingiverse.com/thing:212115
From Thingiverse description:
- Ultimaker main board, will change to Rumba soon
- dual DD2 extruders, direct driving
- dual metal hotends E3D with cooling fans,Fast heat up
- lcd controller
- use prontface,cura or other opensource software
- 1.75mm ABS or PLA filament
- Fast change filament function
- Steel cabinet for power supply and electronics
- Borosilicate glass
- Mk2a 300mm pcb heatbed with 24v,can reach 140 centigrade
- building size 300*300*320mm
- layer thickness 0.1-0.4mm
- Steel side plates
- CNC aluminum connecting parts
- Modular packing
Dual extruder version:
http://www.thingiverse.com/thing:212131
Base version:
http://www.thingiverse.com/thing:212115