using photon as an external usb keyboard for pc

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i remember in the wm6.5 days there was a mod/app to enable using the phone as a usb keyboard for any pc.
just start the app, plug your phone into usb port, and pc recognizes a new HID kb device.
so basic, so useful, so priceless, used it all the time in the field, and saved lugging around a keyboard to every job site.
seems android requires a custom kernel to achieve this without needing an app installed on the pc itself, from the one app i found in the market.
just seeing if anyone has any ideas to make this feasible with just an app, so it could be used on a stock rom, without needing custom kernel.