Something else that occurs to me: am I correct in assuming that there's still one more mass relay left untouched by the crucible wave? That is, the one say out in Dark Space and connects directly to the Citadel. What if the Reapers left one of their own behind to guard it? There could still be a reaper out there, presumably now free from control.
Someone already data mined the files in the EC patch and found what appears to be dialogue text for a future DLC. If it gets made, I think you'll like it.
Original thread on BSN is here: http://social.bioware.com/forum/1/to...dex/12777408/1