The file 'Tiny Dice Tower (no Supports Needed) 3D Printer Model' is (STL) file type, size is 25.9KB.
I modified the Small Dice Tower by scaling it down to 80% of original size and changing the opening to have a pointed arch. This removes the need for any supports to print the opening. I also scaled down the ramps slightly to make sure they slide through the slots even when the slots print messily (as they tend to do due to their angle).
Update: I've added a funnel for the more enthusiastic dice throwers out there. The funnel sits on top and can be printed separately. It needs no supports and can be printed at 100% infill as it is just a thin shell. Funnel inspired by Buchnerb's remix here: http://www.thingiverse.com/thing:1365529
Update 2: The latest file (tower_and_funnel_combined.stl) has the funnel integrated into the tower model, and an improved ramp which prevents the dice from bouncing back out of the tray - keeping them at the front where they're easier to see. I recommend printing this version.
funnel.STL | 29.8KB | |
ramp.STL | 684.0B | |
tower.STL | 7.8KB | |
tower_and_funnel_combined.STL | 28.9KB |