I have been using exclusively Admob in my app for a long time. I currently am getting 320K impressions per day, and want to see about increasing RPM (currently getting 0.30 impression RPM, down from 0.44 in December) using mediation. Is there an ad network that will work with Admob mediation with a SMART_BANNER size? I want a really small SDK size too, I don’t want to increase size of APK very much.
Enhance® works with a few different networks that provide banner ads. We have some networks that are mediated and some that are not. Most using our Zero Code feature.
Follow the link to check out the options available to you through Enhance® : http://fgl.io/MMWA2
Good Luck!
Have you considered adding MobFox to your mediation waterfall?
We are a leading mobile platform (Exchange and Free Mediation),
Supporting all ad formats including Video, Rich media, Banners&Interstitial and Smart Banners.
Our SDK is Open-Source, very light(only 170k) and easy to integrate.
For more information: MobFox - Mobile monetization and mediation platform, Mobile SSP
Also feel free to ping me at Skype: Shahaf Mobfox
or send me an email to: [email protected]
I’ll be happy to help you out 
If you’re somehow still in need of assistance, Appodeal mediates AdMob inventory, increases AdMob revenue, and I’m reasonably confident Appodeal supports SMART_BANNER, but DM me and I’ll double check for you
Link in signature below!
Cheers,
Chris