IF there is going to be an Internet sales tax, it should be a source / destination split at the state level. In other words, each state publishes a single source tax rate and a single destination tax rate and distributes the taxes collected appropriately.
That structure will work to drive businesses to ship from states with a low tax rates.
I think the real effort is to get businesses (sellers) to collect and pay sales taxes to government because there is ample information that proves customers (buyers) do not declare or pay online sales taxes. So this is an effective unfunded mandate on businesses, just like individual income tax withholdings.