Scrap sales taxes and replace them with a single, national synchronized VAT. Say 10%. Sure, sure, it'll never happen because hundreds of thousands of people make their living out of taxes being complicated and screwing every one of you over, but hey, I'm a utopian.
Why do you believe a VAT is less complicated than a sales tax. If the issue is conformity across jurisdictions, a 10% VAT made uniform us just as easy to do as making all sales tax 10%. And a Vat is far more complicated to collect since it has to be assessed at every stage of production.
In addition, a VAT discourages domestic production since it is not assessed on foreign production, only U.S. production and "value added" is taxed which is horrible if you want to promote U.S. manufacturing.
A sales tax is far better than a VAT. We don't need to copy Europe in every single way do we?