Probably a dumb question

2 Plinius, lots of Coda, few Boulder ads on craiglist. Are you searching in the entire country, by map?

Contact the manufacturer and ask for a list of dealers nationwide. Then contact those dealers to see if they have any trades, they would have an idea what kind of shape the units are in, by knowing the customer that traded it in.

Thirded (or maybe forthed) for Echo Audio. Been doing business with them for many years and they are great to deal with and the owner, Kurt, is a really nice guy.

Melbay,

no wonder you can find anything look at the crappy sites you're looking on you won't find high quality equipment on those sites.

https://kahlaudio.com/

This guy sells an assortment of used gear. He sometimes gets super high end stuff but you gotta keep your eye out.