Thanks for the help--they are clearly in many sets.
I think this subgenre of space is really going to inspire a lot of vignettes, a lot of MOCs. Hats off to the thinkers at lego. I collected most of SP3 and thought that would be it for a while. I thought wrong.
I'm not sure I will shell out for the large ADF sets. But my desk has room for two or five Tripod Invaders.
Or I'd like to make a SP3 "Squidtron's Used Space Parts" store with a broken down Tripod Invader (7051), a stripped Alienator (6876), a wheeless rocket launcher up on blocks (462), and hidden behind a bunch of empty hyper-fuel tanks, a gutted Raid VPR (5981). You need to pay extra space credits (100?) to get access to the VPR. Hey Squidtron's risking a lot to provide used Space Police technology...