The "happy little E-tune" posted previously ([mp3 removed]--eventually it'll get a real title) is reinterpreted here on the SidStation synth: [mp3 removed]. Also working on an extended remix of the Sid version, with drums, etc.
The Sid isn't truly polyphonic, so in order to have it play several melodic parts simultaneously you have to overdub them (digitally). This is a pain in the ass.