This suggestion may be completely off the mark of what you were looking for, but every time I've wanted to develop a database driven site or section of a site, I've tried searching for an existing general-purpose PHP script package that does what I want. In all but a couple of cases, I've found inexpensive or freeware PHP script packages that do exactly what I want.
For example, the site you referenced is a relatively basic shopping cart, and it's likely they didn't do the database code themselves; there are many pre-built cart packages available starting in the $100 range, which you can customize using templates to look like just about anything you want.
That won't provide you with any WISIWYG tools for doing the design, but if you're on a tight budget you can stick with the default template(s) of the package you choose and just adjust the color settings and images to do basic customization. If you have some HTML experience, you can edit the templates yourself to do a little more. Or, you can always hire someone to just work on the display code, which is a lot cheaper than hiring someone to build the whole script from scratch.
If you're looking for more general content management solutions, not shopping carts, there are dozens of freeware ones available, some of them very good. I find HotScripts (
http://www.hotscripts.com/ ) a good place to start hunting for just about anything of that sort.
That said...
Now that I've tried to say you don't need custom code, I'm going to ask a follow-up question contradicting myself: Are there any pieces of software that'll easily generate custom PHP (or Perl) code to interface with a MySQL database?
I've got a simple web-interfaced database project I'm trying to get going, but although I have no trouble creating the database structure, I have yet to find a general-purpose database interface that'll do quite what I want (I've checked out DaDaBik and Ministry of Truth). The interface I want is very simple, but my PHP skills are too poor and my time to scarce to write it myself from scratch.
I've tried JaneBuilder, but didn't have a whole lot of luck with it. Maybe I just didn't try hard enough...