This is an unknown Reaper model from Mass Effect 2 (I wasn't aware there were any more aside from Harbinger and Sovereign actually in-game, and since I have yet to actually see this, I'll assume it is unused). Found in the BioD_N7Spdr1_500.pcc file.
i think that bioware originally had plans for more reaper varieties' but due to time and money, they just stuck with some more basic models. pity, I like the variety I saw at the end of mass effect 2 when they were approaching the galaxy.
Well, the strange thing is, they made the models in order to use them at the end. Which means that it wouldn't have taken much more to actually use them in the main game. Since this is in ME2, it would have given them time to implement in ME3. My guess would be more along the lines of trying to cut down on system resources; same with the low resolution textures, it all adds up.
In between capital and destroyer. Apart from that, I haven't really compared them. And since it wasn't used for anything other than the ending cinematic, the scale might not be entirely accurate.
[link] look at the bottom right. It seems to match this model much more than any other reaper. And possibly the one at the top of the screen directly right of Harbinger.
Oh, and I have noticed on the same picture look at the two other reapers left and right of Harbinger, they don't seem to match any of the references you've posted. The one on the right you can see clearly it has no middle "tentacle" and the ones it has seem to be ordered differently from a normal sovereign class reaper. And on the left one the carapace is clearly different from those of all other reapers. So if the one you posted here is either a troop carrier or a processor, then these two might be the other one. Maybe you can find this type in the game files too somewhere.
[link] look at the bottom right. It seems to match this model much more than any other reaper. And possibly the one at the top of the screen directly right of Harbinger.
Oh, and I have noticed on the same picture look at the two other reapers left and right of Harbinger, they don't seem to match any of the references you've posted. The one on the right you can see clearly it has no middle "tentacle" and the ones it has seem to be ordered differently from a normal sovereign class reaper. And on the left one the carapace is clearly different from those of all other reapers. So if the one you posted here is either a troop carrier or a processor, then these two might be the other one. Maybe you can find this type in the game files too somewhere.
That might be the one. It's from ME2.