I don't know how much space does a N64 Virtual Console game takes, but I found a torrent with 46 Virtual Console games (NES, SNES, Genesis, N64, etc) and it had 860MB. Dividing 860 by 46, you get an average of 18MB more or less.
Sonic CD, the ISO with all of the individual music tracks occupies 80MB.
The Wii version of Sonic 4's music uses Wii MIDI instruments so that it wouldn't get past the size restriction of the WiiWare
http://www.youtube.com/watch?v=0fPMlIbTLEY PS3/360 version
http://www.youtube.com/watch?v=BNUhevHZ-Yg Wii version
Sonic CD, the ISO with all of the individual music tracks occupies 80MB.
The Wii version of Sonic 4's music uses Wii MIDI instruments so that it wouldn't get past the size restriction of the WiiWare
http://www.youtube.com/watch?v=0fPMlIbTLEY PS3/360 version
http://www.youtube.com/watch?v=BNUhevHZ-Yg Wii version