Van Nuys VC820 - $120
The ultimate carrying case for portable audio:
Van Nuys VC820. At $120, this is quite expensive. But the fact that, this case is customizable makes it very future proof. Meaning, even if you change your DAPs or Amps, you can be 99.99% assured that it would fit. The case also works well for Hugo 2 like devices. As for the downsides, the case is not exactly sturdy. So it is not something that can take a beating, nor the ideal one for protecting your gear from drops (there's always Pelican case for that).
The internal dimensions without the separators are approximately: 21 x 15 x 4 cm / 10 x 6 x 2-1/2 inches. The separators attach to the walls through Velcro and are easy to adjust. You could comfortably store a DAP and 2 IEMs. If you are alright with winding your cables tightly, you could even fit 3 or 4 IEMs along with the DAP and a few small accessories. Here is a picture of my VC820 with the following:
Lotoo Paw Gold
Zeus + PWAudio No 5 cable
EA Leonidas cable
Sennheiser IE80
I also store a small zipper with eartips and ADEL modules above the DAP.