Thanks for the compliment! Why did you stop your project? I have some diy kits for the 1.3 board available in my shop if you're interested.
I actually own the ARMSID and an ARM2SID.
I did make it play one pre-uploaded track, then I started to think about all the improvements I could make, like reading an SD card, adding a display with a menu, control buttons, a web interface to drag-and-drop and play tracks, etc. Basically, analysis paralysis. I'm still learning how not to do that to myself.