3 head cassette deck.

YY1 said
What I'd really like to find, though is a HQ home single CD player for use at my shop.

They all seem to be changers or DVD.

A little pricey, but they're still made; CD Players - Newegg.com
I'd suspect most are bought by mobile dj's or radio stations, though they're becoming rare even in those applications.

You do realize that DVD players will also play audio CDs.