I just started working on a cross platform app for the Bean and Bean+. So far it has been pretty simple and straight forward. I have built on top of Evothings example app for the Bean. There example reads and writes to the scratch characteristics, I built on this so that it reads and writes to the serial uuid - Bean Transport. I also parse out responses for battery level, temperature, led and accel readings like your Node Red module does
So far I like how simple it is to test and and develop the app on both IOS and Android. Next week I want to look into what would be involved sending a hex file OTA to the Bean. This part will be more complicated as the app would need to split the hex file into smaller packets for the module to receive. Maybe you could give me some pointers on this. I will be looking at this file to see what parts could be ported over into pure JS for the cross platform phone app part of it.
I hope to have my app ready in the next couple of months along with a product that uses the LBM313.
I am happy to share code or help out if PTD is considering making a cross platform app.