Could work but why would you pay that money for the clearwire subscription if you never are going to use the internet in the car unless for long trips.
I never heard of Clearwire but i googled and found out.
Now all i can say is, go for it. Because then you will be the first. Or should i google that too and see if some one has tried this.
Edit:
http://www.autonetmobile.com/Also i know they have that satellite internet for the cars, but that prob gets horrible reception, because you are on the constant move.
http://www.waav.com/index.htmlJust some things i found, when i googled "mobile internet in car"
I still say go ahead and try.