Compact bluetooth remote to start/stop recording pocket4k?

I realize there are phone apps now that can start/stop recording on the pocket 4k. Does anyone know if there is a miniature push button bluetooth remote that could pair with the camera to start/stop recording?

I want to be able to shoulder mount the rig on top of my shoulder and use an EVF to see (ala Zacuto recoil) BUT right now I can't start/stop recording without reaching up on the RIGHT side of the camera which is very difficult to do. Why on earth did blackmagic put a 2nd record button on the face of the camera RIGHT NEXT TO THE OTHER RECORD BUTTON?? I wish they put it on the left side of the lens mount...

I've started looking at doing this. Not sure I'll be up for making a commercial product though. Would there be a market to sell more than 100?
I intended to start with a microcontroller that had Bluetooth, but I brought the wrong one with me on holiday. So I'm just trying out communicating with the camera using a raspberry pi. I think pairing the device with the camera in some simple way might be an issue (how to input the code for pairing just using a few buttons).