Button Icons - I would like to add custom icons

I am in the process of trying to build a product configurator using Website Builder.  I have a few other questions on the board about customizations.

What to I mean about Product Configurator.  Think of the Car sites, I want a Ford Truck, and it should have 4 wheel drive, and it should have a specific engine option, and in the end, I have configured a Truch that I like.  Well, I wantr to do something similar on my site.  To do this, I need a customizable category widiget, better filtering, customized product / accessory relationships.  Let's call that enough for now.

Thomas