What i would like to see are Wood Planks, Stone, Cave wall, Rock, water and other blocks have the properties of the wild grass.
Maybe have them have a set group of pixelmon they can spawn.
Rock: Rock type
Cave: Ground types
Wood Planks: Ghost "wanted this for a ghost tower"
Water: water types
Another idea would to have block that makes blocks around it have the properties of the wild grass. Lets say you place the block, then open up a GUI and set what pixelmon you want to spawn in a set are 3x3, 5 x 5... ect around the block.
Then you take the block you want to camouflage it as, and shift right click to "hide it", then any blocks on the same level and around it can spawn wild pixelmon.. like the tall grass. (Not untill you walk on it though)