This particular request is an old one, but there is no solution and I created a custom extension - [Improved Navigation
Home page layered navigation is NOT the main feature of the module, but handy one.
More important that with the module you can
* create shop by brand , shop by actor or any other attribute blocks
* show linkable attribute images on product page
* add attribute description (like author biography or manufacturer description)
* add images (logos, icons) to attributes and show them in layered navigation
* sort options in the layered navigation, show them in different styles (images only, 2-columns, dropdown)
* use custom price ranges
* generate all brands block
* create manufacturer landing pages and many more ...
Your feedback is much appreciated.
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