Alexander Krauss of ByteBoosters writes in to let us know that their Apple IIGS Stereo Sound Card and Digitizer with line-out is now available:
DarkSound by ByteBoosters. Take full potential of the IIGS Ensoniq sound chip by enabling Stereo output. Furthermore use the Audio Digitizer feature to sample sound and use them on your IIGS with virtually any IIGS digitizer software such as AudioZap.
Head on over to eBay to get yours now!