Advice on creation of an online catalog/store, please.

Question

I want to create an online store of food products using a  format similar to the Flexstore Sample application. If you are not familiar  with that application, you can see it here: http://examples.adobe.com/flex2/inproduct/sdk/flexstore/flexstore.html.
The sample, of course, works fine, but it's a catalog  with a total of 18 products, not likely found in real life. The project I am considering  would have about 1200 products; there would be 24 categories, each containing a  number of products rangin from 2 to 460. Of course, I know better that to start  out loading all the products as the little sample application does.
I envision initially loading one of the categories that  has between 50 and 100 products (I did one version with 220 products and it  worked OK). But I have not yet even come close to figuring out how to go about  this.
Here are some thoughts/questions:
Initially load one category? – not one with a  lot of products, then keep adding to the total catalog as users check new  categories.
I see the checkout portion of the program as a Flex  module, to be loaded only when a visitor get to the point of checking out.
How do I handle a collection that keeps growing?  – after 250 or so products, things really start slowing down.
How do I handle that one category that has over  400 products? A separate module? Break it down into subcategories?
And there are many more issues, I'm sure some I have not  even thought about.
I would love to hear any comments/ideas/suggestions about  this. When the store is ready, you'll be invited to the opening.
If anyone knows of a real-life catalog/store application made in Flex, please point me to it.
Success to all on this new year,
Carlos

Answer 1

From the replies so far, I can see that a little more information about my project is in order:
For this project, I am working from a merchant datafeed, so I already have database tables with all the product and food category data – I also have the URLs to all the images – and actually the images on my server. So archemedia, I have no problems bringing the data from my ColdFusion server into Flex – a recordset of 1200 rows is nothing.
My concern and the bottleneck here is creating and displaying many thumbnails at one time. I have to rule out creating and displaying "All Categories" the equivalent of "All Series" in the Flexstore sample (see mi original post on this thread) – that works fine in the sample with its total of 18 products, not so well when you have 1100+ items to display. That is really the part of this project about which I need advice.
Here is what I am thinking: starting out selecting and displaying X category (one with no more than 75-100 products). Then, bringing in one category at a time, as the user selects them in the ComboBox. I guess I will have to split categories containing over, say 100 products into smaller subcategories.
It helps to just hear feedback, so I want to thank all of you who have already replied. And y'all please keep those ideas coming, ya hear?.
Carlos