* A wallwart doesn't add any noise if it's not a switchmode supply.
* If you can't find a decent case (Pactec PT-8 should work, as well as the aluminium profile style case I used for fnpSID) go the sammichSID route and have one made @ ponoko
* You will have a hard time making sth as small as sammichSID without a custom PCB as you need core8, DINx4, DOUTx4, bankstick, PSU and 2 SID modules in there.