Hi,
i've been working with unity for 3+ years now, mostly doing mobile/web reskins as a freelancer and developing android games as part of a 2 man.
I can provide links to some examples if you want me to.
While working with unity i integrated several different ad networks, i could finish the plugin within a few days for you.
If you got any questions or want to know more just message me either here or on skype(mh5414).
Thanks for your time,
Marvin