We just finished our latest creation: the x0x-heart! It is an SMT replica of the TB-303′s analog voice, complete with VCO, VCA, VCF, and envelope generators. It’s meant to be the base upon which you can build a highly acidic synthesizer.
x0x-heart slaved to a 303 (Note: the camera had some issues capturing the high resonance sections, better vidoes are on the way).
It was designed to be small, easy to work with, and low cost. All of the important I/O points are pinned out on 0.1″ header for easy transplanting into your designs. There is even digital control of cut-off, envelope modulation, and waveform select, along with the standard, accent, slide, and decay. So check out the x0x-heart product page, and if it seems like something you can use, swing by the x0x-heart store and pick one up.