Steve Duda of Xfer Records has (re)released 8-Bit Shaper, a bent waveshaper effect plug-in for Windows and Mac.
back from the dead, also made an AU version and updated it (GUI improvements, performance improvements, bugfixes).
disclaimer: The sound is *slightly* different than previous, so if you happen to have the VST from 2006 in saved projects I would recommend to not update.
8-Bit Shaper is available as a free download for Windows and Mac (VST/AU, requires OSX 10.5 or later).
More information: 8-Bit Shaper