Sequential Circuits Six-Trak

via this auction

Mini Korg-700

via this auction

Roland SH-2000

via this auction

"serial number 5057**"

Korg Polysix

via this auction

Bliptronic 5000 LED Synthesizer

via this auction

Update via Computer Controlled in the comments: "these are $50 new."

Link on ThinkGeek

TECHNICS SX-WSA1

via this auction
"Technics says features include:
64-polyphonic GM synthesizer.
5MB PCM ROM. The samples are mostly GM-based, but there are some interesting waveforms like Roland D-50 / D-110 and KORG M1 as well.
3-OSC architecture.
The filter has resonance but no envelope.
Distortion" can be added to each oscillator. It's actually fast vibrato - a kind of Roland JV's FXM, but KN2000's modulation frequency is lower, and it sounds more like vibrato. With "Growl" option, the FXM is applied only to the attack portion of the sound.
One "Digital Effect", one reverb and one "DSP effect
The digital effect includes "Repeat delay", which seems to loop the attack portion of the waveform.
Drum samples are looped to make reverb-like effect - a rare feature first implemented in YAMAHA RX5 / PTX8.
A big 320*240 LCD display with lots of buttons around.
FD drive to store sounds and sequences.
The data can be stored via MIDI SysEx."

Waldorf Pulse PLUS

via this auction

"The de facto analog synth, killer sounding and can also convert MIDI to CV and CV to MIDI (extremly rare).stereo out, several pair of cv and gates in AND out. FILTER IN ! (to die for)."