[joshf]

Here's the 5 minute way to do show all products per page:

include/search.php
Find:

        for ($i = 5; 50 >= $i; $i = $i + 5) {
            $perPageValues[] = $i;
        }

Immediately after that, add:

        #Show all products per page
        $perPageValues[] = 999;

skin/common_files/customer/main/per_page.tpl
Find:

    <option value="{$value}"{if $value eq $objects_per_page} selected="selected"{/if}>{$value}</option>

Replace with:

    <option value="{$value}"{if $value eq $objects_per_page} selected="selected"{/if}>{if $value == 999}View all{else}{$value}{/if}</option>

Enjoy!