I ran into this just last night. I was setting up my Xbox to just be a, well Xbox and not a be all emulation machine. When I modded my original system years back, I backed up my data but since then the drive that data was on died. Not a huge deal except I was getting Karaoke Revolution Party set up and I used to have the DLC (which was expensive). Well, don't anymore and no way to redownload it officially.

Thankfully kind folks who archived that stuff had it available, so I could get it. So if anything stuff is "out there" like aliens and Tommy Chong, but no longer in the legit way.