I did some similar stuff like this years ago (most from the mid 00s). However, most of it is so bad that I can't post it. It's in everyone's best interest. Here was one of my better produced one man acapellas (Ralphcapella, son) even though it's of a lame radio song and not a lame video game song.
EDIT: Screw it. I'm posting them. They are horrible. They are from like 7 years ago when I was still in my early recording/learning phase. Most were done at like 3 AM. Forgive me. You've been warned so hard.