I have made two variation of the stand:
The first one is the standard size common with all figures and larger Halo Grunts. This stand is compatible with almost all Mega Bloks figure that take three pegs to stand up (See pictures).
**The studs for this stand was off by a micrometer, so the minifigs don't stick to it as they do to the original ones. However, for the purpose of displaying the minifigs this stand will do.
The second is for the smaller Halo Grunts that were in the first few Minifig series and sets. This stand is also compatible with Lego Minifigures that only use two pegs to stand up (See pictures).
Link to the stands: http://www.thingiverse.com/thing:287039
I hope this helps anyone looking to display their Mega Bloks and Lego Minifigures. Please like and add this to your favorites. Thanks.