Is there any traction on ‘Data Only’ wireless plans which augment your primarily carrier?

E.g. when you reach the allocated capacity of the primary plan, one of N secondary wireless providers may be selected ‘on the fly’ or in  settings.  Each wireless provider may offer their own competitive ‘data only’ plan.  The subscriber may choose a “10 GB for 10 USD.”

Alternatively, the consumer may direct traffic of a certain type, e.g. Network packets for movies to ABC wireless.

Prime example, my family shared plan offers 10 GB to share among the 4 of us.  One of us, for the last two months, chewed up our data plan.   At 75%, 90%, and 100% AT&T sent us warning notifications, which was very good.

After we bust the quota, we are automatically charged one GB for 15 USD.  It may be just me, but that sounds pricey.  Both months I stopped the data component for one of the phones.  Also, a great feature AT&T, but it doesn’t go far enough, block only streaming movies when not in WiFi.  I’d prefer if the middle tier, the wireless solutions management implement the feature.  The kids don’t have access to it as would a device implementation.