How many Sift Head games are there going to be

Well i cant tell you how many there are going to be, but i can tell you what's out now that I'm aware of. theres sift heads 0, 1, 2, 3 and 4. Those are the ones that follow vinnies story, and then theres also one called sifting with shorty which is his girlfriend (you see her at the beginning of sift heads 4). Those are all the ones im aware of.