Actually in 22 states in the US they are activating using the SST (streamlined sales tax).
List of current states participating are at
www.streamlinedsalestax.org/index.php?page=state-info
I have customers in Kansas states that require this already and there is NO minimum sales volume required. When we developed our own cart, we had to build this in to do real-time look-up based on the destination. We've had to deal with this for over a decade now.
We've switched to using x-cart for these clients because as of last year x-cart includes taxcloud as part of their core package. But x-cart it is over kill for most of our small business clients that would rather use Joomla as the CMS.
This really is a big burden on the small businesses (which we also target) and why we like Hikashop but this is one of the glaring weaknesses right now (really the the only one I can think of).
The current proposed Fairness Act is just formalizing this across all states but I'm not sure it will supersede the existing state laws or work in conjunction wit them. It needs to get past the US Senate first before we will know for sure.
But long term, taxcloud is the best solution I've found as a service. We used to do it state-by-state as they all used different technologies and most other tax services require thousands of dollars a year. They are the best deal out there right now.
But this is a real issue, affecting small business in these states now.
I'm going to talk to one of our PHP developers to see what it will take to do a module, but time and money tend to get in the way of these special projects. But this is going to have to happen for all of us I think in the US. I think it would be ideal if this was made a core part as this will be come an ever increasing problem for all businesses, small and large alike.