Korg has released iPolysix for the iPad. This app is inspired by the Polysix synthesizer from the eighties and consists of two synthesizers, a drum machine, two Kaoss pads and a sequencer. According to Korg this app is analog, but the iPad is completely digital of course.
I have no idea if this app is a good emulation of the Polysix synthesizer, but the reactions of users and music websites are positive. The iPolysix is available against the introduction offer of 14 euros (50 percent discount) until next December 31st.