I know that it seems a crazy printer but I've printed the mechanical parts and now it seems not so crazy. The printer uses an arm to manage the extruder (not yet fully tested). The advantages are the large flexibility of area printable and the very low cost of parts. I've used less than 500g of filament, 4 smooth rods, 4 linear bearing and 8 circular bearing (less than 20Euro). I've attached here also the firmware based on Marlin. WARNING: it is a very preliminary version and it must be completed. Currently XYZ movements are partially tested. I'll keep you informed about its progress.
Software: OpenScad, Cura
Printer: Prusa I3
Filament: PLA 3mm
Support material: yes (pattern 15%)
Temperatures: 195° extruder, 60° hot bed
Fixing method: adhesive tape