Pastel E-Business
Hi - When it comes to accounting integration, Pastel's e-commerce solution is the best integration you're likely to find - it's very extensive. It reads inventory, pricing, stock and customer info from the accounting to publish to the online store. Then it writes web orders back into the accounting system. 2-way integration like that is hard to find with other e-commerce solutions and if your client is on Pastel, at least you know this will work and be continually updated as new versions of Pastel are released.
I've helped a few clients go live on this platform and I've found that for basic e-commerce this works pretty well.
Bear in mind that this product is much cheaper than it was a few years ago so, as a designer, you can make money from styling the site while Pastel takes care of the heavy lifting for you. Price-wise, you should be able to undercut a custom-integrated (to Pastel) e-commerce system and still leave room for yourself to make money from the design.
It has been criticized for being difficult to style nicely, but the developers have improved this over the last year and if you know your CSS and HTML (as good designers should) you'll be able to style the store without much issue. They currently don't give you 100% control over the templating but there's still lots of room for customization on the look and feel side.
It's an off-the-shelf product so if your business has very specific needs from a website, with processes that are outside of the ordinary flow of typical e-commerce solutions, then this isn't for you. For 90% of the sites though, where all they need is a simple way to sell stuff online, I think it's worth a look.