The semi-interactive walkthrough on the website is really cool, great way to show the UX.
I've always wanted to use a round display and an 18650 to plop a mini bike computer into my headset (replacing the cap). There was a Kickstarter years ago for a project doing that, but it seems to have fizzled out
If you mean that you push a 18650 inside the steerer tube and have the display at the cap level - how do you preload the headset then? You need to pull the steerer up somehow and it's done via that cap and a bolt that goes through it into a compression plug/star nut inside the steerer. If you place something under the cap it needs to fit between that bolt and the inside of the steerer tube, which 18650 can't.
Some modern headset designs don't use the top cap to do that. There's a bunch of products that exploit that to put toolkits, spare CO2 canisters or whathave you in that spot.
Sure, threaded headsets (hardly modern, but they do still make bikes with those) don't use top cap, but they also don't have a hole at the top, which products you are talking about?
PS. I searched and found some in-steerer storage. It's not a headset but essentially a hollow compression plug replacement with a top cap moved to the bottom. I have never seen a road fork with a hole at the bottom so it is likely limited to MTB forks and, since there is no compression in that thing, it might be not very safe with a carbon steerer.
I ride several bikes so I would not know what to use the in-frame storage for. I want the things like repair kit (with batteries) and lights (also with batteries) to be movable between bikes so the batteries are charged in time. Even if all my bikes had in-frame storage it would be a chore to move its contents.
I've always wanted to use a round display and an 18650 to plop a mini bike computer into my headset (replacing the cap). There was a Kickstarter years ago for a project doing that, but it seems to have fizzled out