As per your comment: ~100 items seems almost managable if you accept scrolling, depending on how much text is necessary (image only, image + title, description).
You could combine a preview (large image, text, description) with a thumbnail gallery, and cheat a bit with mouseovers, like this:
download bmml source – Wireframes created with Balsamiq Mockups
You have one of these blocks per main cat ("Kitchen"), the thumbnail gallery is grouped by sub category ("fridges", "stoves"). Mouse over an image to show large image + title + description, click for details.
Without mouse over, the large image could cycle through available products (you may want to sync that between the blocks), so they all change at the same time. Order of the big blocks could be randomized per visit or day, determined by promotions or depend on incoming source.
I am still not sure if this is a great idea. A touch interface would require tap to select, and e.g. tap again or double tap for details. It's a lot of information, clutter is hard to avoid. It would desperately lack some empty space. You are fighting scroll vs. image size.
(You could get more cues from image searches. this is probably the easiest way to demonstrate your clients the image size vs. number of items tradeoff. )
It could work for visually appealing products where the images at lease have the same photographic style.