I'd buy a NEW Sony SCD-5400ES for $1500 - long break in time, but well worth the wait. They are available at the Sony on-line store if you have trouble locating a dealer with stock.
I would not waste my money on a used CD player only. I would get something that has a DAC like the Oppo but better for 2 channel. Most HE CD/SACD players are coming out with DACs included like Cary, Esoteric and DCS. Used Esoteric units and others will be showing up here on AudiogoN in the near future so I would wait if I were you.
Got a MHDT Havana Balanced and OMG! This thing is amazing. It's the first time I've heard digital sound this pure. Live records sound, well, live! And this is with the Oppo as a transport (which will change when I find something suitable). I have lots of CDs and not nearly as many LP's but I tend to pick the same records all the time... That will change!
Marantz..Marantz..Marantz...very emotional organic, warm quality with outstanding dynamics and detail. You can pick up a used Reference model for $1500.00. Much better sounding than Oppo. Don't get mods! Just get the Marantz...Music Direct online currently has a used demo of the Marantz Reference SA-15S2 in mint condition for $1599 which is the KI-Pearl without the copper shield on the transformer. They might let it go for $1500.00. Great staff to work with.