I’m in no way affiliated with this eBay seller, but this came up in a search, so I thought I’d share.
A lot of 12 SIDs are available. So, if you’ve been putting off building a MIDIBox SID due to parts availability, now might be the time to reconsider?
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F283767607715