The German magazine KEYS has released a special VSTi from VirSyn: The microTERA Synthesizer.
microTERA is a fully functional Mac and Windows stand-alone and plug-in and is based on a mixture of VirSyn's TERA and Cube. Sadly it isn't available for download but it is included on the KEYS CD-ROM cover-disc 11/03.
KEYS also recently released a special VSTi from Native Instruments: The Carbon-Synthesizer from the Reaktor 4-Library. The stand-alone and plug-in is based on a special Reaktor-Session-engine called Session-One. The KEYS-Carbon-Synth is fully functionally (Mac and Windows) and is also included on the KEYS-CD-ROM.