It'll be a blast in the past!
Anyway, here's the Sonic one...
http://www.kikizo.com/viewer/imageview.asp?sonic-unleashed-interview/sonic-hd-fan-art-by-orioto.jpg
The difference is, Mario had transitioned well to 3D, so there haven't been big clamors to revert back to 2D style gameplay (and we had New Super Mario Bros., anyway). Sonic had little success on 3D, though...