Looks pretty good. There are some places it needs a little more flexibility, but in general it seems pretty strong.
An example is in the "settings" area of the Admin section, for "order status" there are three options which can be renamed but often there are other "status" items a company may need. "Backorder" is a good example of tihs. Often people are willing to order an item the really need, even it the order is on "Backorder" status as long as an expected shipment date is available not too far into the future. A status for "pending return" might also be useful if the store will accomodate return items for physical goods.
Under "Handling" you allow for handling to be billed per item or per order. Good, but it is this also assignable, somewhere, by caterogy of goods sold. For example, If I have the handling charge set "per order" but the order is a downloadable item, what possible "handling" should be charged? Same thing I guess applies to "per item." in that particular instance.
"Shipping" falls along the same lines. You allow for the creation of new "methods" in the shipping area, but I didn't see where those got applied. In addition I would be very hesitant to apply any "shipping" to a donloadable sale and in the "Products" detail page, did not see where shipping could be applied per product either. I may not have researched the system appropriately to find it and appologize if I missed that.
Under the "Reports" section, there are lots of reports that come in handy in a system this powerful. Such as a "sales by period" option. Viewing by period makes it easier to compare "this week, this year" to "this week, last year" and can shouldn't be too hard to create.
The "payment gateways" I didn't see a way to create a new payment method, though you do have an edit area which insinuates that you could add the capability to create additional payment methods and gateways, such as PayPal and Google Checkout. That addition would probably be a huge plus for many.
In the "Just listed" template, an image might be good. It exists in the product template, but doesn't show in the "Just listed" listings. May be by desing, but even a small image would probably be nice there to the left of the listing
Looks like you made each item SEO capable by keywords, and the same is true of product categories. That is very useful and good foresight on your part.
All in all, it looks pretty strong and pretty easy to begin understanding. That is probably the best part of it. I could figure out most of what you intended and how it was supposed to be used in a short period of time. Took probably about 20 minutes or so of nosing around to get to a point where I felt I was ready to start using most of what was there.
Clean interfaces, neat, crisp layout. If the system also inherits the "Skin" and "container" from the main site, I think you have a winner. Separately skinning the "store" on a sight may sound neat, but I have seen too many stores that look "disconnected" from the main site, givning a sort of wierd feel to it all.
Hope that helps Frank. Looks like a strong job so far.
Clay