Another 2 months...nothing. When is CS-Cart going to take the next step that a ton of other cart software has already taken a long time ago?
One of the things you may not realize (and why we abandonded trying to do anything with Amazon) is that they change very rapidly. I.e. you spend a couple of weeks developing to an interface and then 2 months later they change it all. Amazon is a maintenance nightmare for 3rd party developers. But like Google, there's not a lot of room to push back. So you either commit to loosing money by staying in a state of constant development/release cycles or you decide to leave it for someone else.
This is just my perspective from my experience. And yes, using a 3rd party multi-marketing channel would push that variability off onto the channel. Used to be interfaces to the old shopping.com and other multi-channel folks. It wouldn't be that tough to do but you should choose wisely otherwise your recurring costs are going to eat every bit of your profit.
We're happy to provide a quote for any integration you choose.