Imagine having the solid doodle bed enclosed into a rectangular tube like chamber. On the same level as the printhead carridge, there is also a sand distributor chamber riding along Y axis. The print head needs to be parked in home position while this distributor goes along y axis and deposits fine sand. The sand essentially hugs the print on the print bed. The distrubutor has a scraper that removes extra sand exposing the last printed layer. After this sand sweep is done, the print bed shifts down and printer prints next layer.
The print is still done from ABS or PLA, but the sand is used as the support material.

To make this mod possible the ardurino controller needs to be able to control a 5th stepper motor.

What do you think?

Might not work as well as SLS, since sand might not be able to hold the parts when print head is dragging over them...