Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2171912.
This is a remix of both abrandi's mod of 3dspool_canada's feet and TEN1964's mod for the i3 PLUS to be used with Azza's popular zBraces.
This version takes abrandi's mod in that it allows to use two nuts on each foot in order to stabilize the gantry in both directions and then adds TEN1964's mod to provide full base leveling capability.
I also used Azza's "Z braces for Wanhao Duplicator i3: http://www.thingiverse.com/thing:921948
In addition to my versions, just print the top_right, top_left and 4 of the MK2 balls from Azza's braces.
Use these with Anti-vibration feet for Wanhao Duplicator i3 Plus from shusy: http://www.thingiverse.com/thing:2130829
Or purchase Threaded Furniture Glides (SKU 193 637) 1/4" thread with a press fit threaded plug from Home Depot or your local home supply store. (For my setup, shusy's side feet for under the gantry tower were not tall enough, you may or may not need to change the height of those based on how much you need to level the base).
See http://www.thingiverse.com/thing:2021974 for more details on the leveling.
Note that the way the leveling feet positions are away from the printer frame, it puts additional pressure on the mounting screws, more so on the front bracket parts. Do not skimp on the infill, go with 70% or more. If you don't use a high infill and you try to tighten the M5 screws to where they should be, the infill can give way and the part will crack at the layer central to the screw mounting hole. I learned the hard way and had to reprint the feet.
Another way to help relieve the stress would be that once you have the base leveled with the furniture guides or printed feet, that you create for blocks that match the height of the lift that the feet give to the printer and place (glue) them under the base of each corner directly below the screw position to help support the weight.