I don't know about other hardware but the trezor bridge is accessible via js, how else they do their client side web wallet?
EDIT: Either that or a dedicated android app, that would be really nice.
A trezor has a "bridge". It's basically a plugin, which connect a hardware to a browser. Neither Keepkey or Ledger has it.
Let's start from the beginning. As fare as I got, you would like to be able to start a masternode using a cell phone?
It's a great idea, but this would be a completely different project.