When it comes to the exercise of 'how many orks can I possibly field for x points', Madboyz are the answer, as they're only 5pts. a pop and can be fielded in unlimited numbers (again skipping the pesky bigmob size cap) as Deathskulls. They also will be utterly out of your control about half of the game. If you want units you can actually control, WIldboyz are the answer and Snakebites can field them in unlimited numbers. If a unit's size exceeds 21, they actually become cheaper than madboyz - still no gun and no save though.