The ES100 has a 350mah battery right? Something modular/piggyback would be nice (like Moto series smartphones) for times heavier is not a nuisance and chillin' like a villain is preferable. Snap extra battery on for 3x battery life. I wonder if an external detachable clip could double up as an external antenna? I don't mind metal but the clip as is seems like an afterthought. With metal casing and/or bigger expandable battery the clip would to be more substantial or other method to make your headphone wires "disappear". I have a note but am at work and haven't slept well in days. Perhaps, with some reminders I could draw a couple sketches and pass it on to Radsone. I wonder how enthusiastic Radsone is about this. I believe they are South Korean company. Startup or posing under different name? Something the size a Nokia 3310 or perhaps Nokia e71 would be cool especially if it could pump some juice into something 250 ohms. That might be a little ambitious though. I have really been getting[in into earbuds recently because of the ES100. Heck, as is, it can't make my Beyerdynamic COP (16ohms) sing like my JDS Labs C5D can. My BD 770 250 ohms work but really only serves as really passive background music.
Clip-on external battery would be fine with me as an option. Perhaps there's a even 3rd-party power bank that could be DIY'd in place. As for an external antenna: a clip form factor and location may be difficult to optimize for good reception. I've designed products with 2.4 GHz antennae, and have researched radiation patterns and antenna configurations [
https://www.panamax.com/products/all/compact-power/smart-plugs - those use inverted-F PCB antennae. Antenna impedance matters.]
Good plastics can also be substantial. In the portable world, lightness is a
feature. There are heavier options available with more power, but the ES100 currently stands alone with its feature set, performance, and light weight. A larger, heavier form factor sounds like a different use case.
I know, I too want all of my DAC/amps to have the configuration options of the ES100. I'm glad I can take this one anywhere, because my iPhone Xs sucks at EQ, and I don't want to spend eternity leaving a flaming trail of B-stock returns in my wake while trying to Goldilocks my way to the perfectly-tuned-for-me-out-of-the-box earphone.
Radsone is an established company, known for DSP IP, among other things:
https://web.archive.org/web/20110507074813/http://radsone.com/. I don't know how much of their focus is on EarStudio, though, They've revealed some protos of future non-wireless products (ES200, ES400), but I haven't seen any release dates.