Xhip synth

In 2003 it existed as a stand-alone application ("acid synth") and someone suggested that it should be converted to a VSTi.
Xhip allows you to produce the highest quality dual-oscillator polyphonic synthesizer sounds, similar to classic poly synthesizers of the late 80s. Strings, synth pads, basses, leads, organs, pianos, percussion, bells, vocals, sound effects and more are demonstrated in the included bank.
Features:

• Two oscillators, filters, envelopes and LFOs. 
• Sync and xmod. 
• Oscillator (super-saw) unison. 
• PCM (samples) as oscillator waveforms with anti-aliasing. 
• Ring-mod. 
• Audio-rate filter modulation and saturation. 
• Waveshaper. 
• Sample-accurate modulation. 
• Voice level unison.

http://xhip.net/