Product Map (A-Z) for X-Cart solves this problem by providing alphabetically sorted, easily spiderable product links over multiple pages.  Featured products are also listed first so they're ranked higher by search engines.

Features:

• Product Map itself has seo friendly urls for increased spidering of the map (Optional).
• Allows you to specify products for display on your main product map page to weight them heavier with search engines.
• Configure the number of products to display per page.
• Choose to exclude products from display.
• Works with membership levels so the user sees the products they have access to
• Configure which letters you want to provide the user to sort by
• Choose to show product details, including thumbnail and short description, or just a simple text link
• Displays featured products first in listings so they are given prevelance
• Works seamlessly with popular SEO mods such as Custom Dynamic Search Engine Friendly Links (CDSEO)
• Use of CSS to minimize html code for easier search engine spidering