Looking at the OP, there were two very specific statements that were made, and they both jumped out at me:

"we taught him multiplication one afternoon while he was doing flips on the bed - but he doesn't want to read more than the standard reading given out at school."

In the first statement, the child learned an advanced subject very quickly while simultaneously engaged in physical activity. This suggests a kinesthetic learner. And the second says he doesn't prefer to read, which is a sit-still-and-quiet activity, again suggesting a kinesthetic learner.

So, how do you get a kinesthetic kid reading... rocking chair? Exercise bike? It depends on what you have available and/or are willing to spend. I'd say it's at least worth experimenting with, though.