I'd vote for no logo on the lower spine though. IMO, the simple "Nintendo Entertainment System" on top is enough. Any more and I think you'd lose a but of that simple elegance.
Been leaning towards v2 myself, using the bottom for the publisher/dev logo. I'll try without the bars on V3. They definitely aren't doing it for me. Hadn't thought about using the sprite on the spine. I'll try that out, but with just a silhouette.
Oh man. Oh man. Oh man. I love it. Of course, it's well on the record that I like minimalist design stuff.
Upload for sure champ.
Your links are all down I recall really digging your covers.