Hey.... something I actually know something about!!
the worst thing about ghillie suits is that they are made to do the opposite of miniature painting. they make you disappear. NOW that said there is some ways we can do this. your best bet is a ghillie cloak. now these are similar to suits BUT are not conforming, just a drape.
now BOTH your spotter and you shooter will need to be camo. Snipers work as a team. with one prone and one standing you have the options of making you suits look realistic. I have collected some pics myself to illustrate.
These were from here:
they are not good....
BUT are what Im trying to say about drapes. use a "higher thread count" material for your cloaks, like real cloth.
now here is a good ghillie pattern:
these are from Dakka:
Very realistic for miniature, using medical guaze. 2x2 or 4x4 should work just fine.
another method that works well in a desert area is flaps. not too many bushes in the desert but these work OK in a pinch and are actually common in an semi arid environment.
dont know how you would recreate this though.
you could always use a cloth drape, coat in PVA/White glue and drape your mini. the layer static grass from the bottom to the top, but this would take lots of patience and alot of grass.
key points in doing this.... both are in suits. do not place a suit below the waist on the front (this will always be on the ground but DO wrap around the front of the chest!). and if your layering, layer from bottom up overlapping as you go to create "rippling" that helps break up your silhouette. hope i helped!!