@nprofile1q...@nprofile1q... ... here's a wonky idea I've had for years but never did anything with: At least iPhones (but I'm kinda expecting Android to be able to do this as well) can speak BNEP, which is just regular Ethernet frames encap'ed into L2CAP.
If you could somehow speak Ethernet, TCP/IP and then HTTP, you could potentially just connect via Bluetooth to an unmodified iPhone/Android?