Actually, I'd possibly prefer a portable dac+amp that is powerful enough. The Topping G5 looks perfect, I'm just not sure about the quality control and battery degradation over time. This way I could use my phone, laptop or basically anything as a source. I'm also a bit lost on minimum power requirements. Some say 0.5W is enough, some say you'd need 2-3W for headphones with similar sensitivity. I know about the calculators but those seem to be very optimistic compared to the subjectivistic advices. I have a E1DA S9038 G3, which provides around 0.5W into 16 Ohms. If that would not limit the performance of the Noire X, maybe I don't need anything new to power it.
But I agree that the problem with IEMs is the IE part...