OnePlus One already has a decent port of Android 7.0 Nougat
updateing has come through with this build for the ever-customizable OnePlus One. Compiled straight from the AOSP source, the release notes suggest that 'almost everything works'. Known issues include video hardware encoding, which prevents the video camera from recording properly. The stock keyboard doesn't work either, so users will have to install a third-party alternative via ADB, and there are several other noted issues besides.XDA-Devs member
As you'll surely be aware, the OnePlus One will not be updated officially beyond Android Marshmallow. So if you're rocking the device and dying to see what the fuss is about with Nougat, this could be your way in. Keep in mind, though, that you're not going to achieve the smooth, unadulterated experience you'd get on a newer flagship running official Android 7.0 firmware.
For more info, check out the source link below, and let us know how you get on if you do happen to dabble in this tailor-made ROM.