Yes, what I have done in the past is to create a new field in the product database called taxable like so:
`taxable` tinyint(1) NOT NULL DEFAULT '0' COMMENT 'Sets whether the product should be taxable or not i.e. children's clothes are not taxable',
This also needs to be added to the eCart Object as a new column and the value passed when adding to cart.
Then I create a rule that says do not charge tax on any items in the cart where the Taxable Column value is 1
Hope that helps