printer cartridge site

Hi All,

I am currently developing a printer cartridge site and am struggling with how to structure the data.

I need to search on Brand (easy enough), Printer type (easy enough) and then printer model.

There are around 35000 printer models and maybe 5000 type's of cartridge.

Do all the printer models have to have their own category?

or

Do i list the all printer cartridges in products and then assign printer models to them as attributes?

So far I have assigned categories to the printer type (laser, inkjet, fax, etc)
also to brands ( brother, dell, hp etc).

I intend to have 3 drop down boxes that begins with printer brand, then type then printer model. A similar version can be found on http://www.lasertechgroup.com/

thanks for any help