Hmmmm...that would be nice, but highly unlikely as those are two very different networks. Wireless data is far different from the fiber/copper that makes the cable/DSL networks. Personally, I find the 6GB data plan for my iPhone is quite reasonably priced at $30. I tether for a couple of hours a week and use my phone quite extensively - I haven't gone over 4GB yet in any given month.
Switch to Teksavvy. At Teksavvy for $30 you get 200 gigs of data, a more reliable service, and a company which cares for you. And I agree pricing is ridiculous...