@Hapster: I've got the CEntrance HiFi-M8, the HRT microStreamer, the FiiO E17, and the beyerdynamic A200p (on loan). I'm doing a review on the A200P that I should have up sometime tomorrow.
I've worked through the issues of getting iPhones, iPods, and iPads to talk well to these DACs. The A200P is definitely the most compact solution out there, and the microStreamer is a close second (but the microStreamer needs the Lightning-to-USB Camera adapter to work). Here's a picture of the M8 (left) with an older iPod Touch and the microStreamer (right) with an iPhone 5.
They all have advantages and disadvantages, though.
On the Go-Dap DD Socket1, it is only a DAC. Here's a thread on it.
VentureCraft has moved on to other DAC/amps, though. I think this model is pretty old.