>Ok, that stumped me - I've always considered a category to represent a range of products, not a manufacturer. How is that possible? What you did with Denali is what I had in mind.

I decided from day one to use
1: a root category for manufacturers, where the individual products "live", that follows a logical structure as per the manufacturers families. This is the base, from which all are linked.
2: a normal product category structure, with linked products / a generic description of a product family, leading to the products in 1
3: an enormous Bike-Model-Year structure where the individual products are linked per compatibility into a year

1: is accessed through a category drop down per "manufacturer" but as a category name, not as the product manufacturer assigned in the db.
2: is accessed via normal category sidebox omitting results from 1 and 3
3: is accessed via triple dropdown

So, no use of the core "manufacturers" at all, as if you want some categorisation, you can't. Apart from filtering a product listing of mixed products.