You can use Karabiner (formerly KeyRemap4MacBook) to remap the eject key. Short presses of eject won't get registered unless you also install NoEjectDelay though.
This private.xml maps the eject key to a power button or key:
<?xml version="1.0"?>
<root>
<item>
<name>test</name>
<identifier>test</identifier>
<autogen>__ConsumerToKey__ ConsumerKeyCode::EJECT, KeyCode::VK_IOHIDPOSTEVENT_NX_POWER_KEY</autogen>
</item>
</root>
This makes pressing eject open Finder:
<?xml version="1.0"?>
<root>
<vkopenurldef>
<name>KeyCode::VK_OPEN_URL_FINDER</name>
<url>file:///System/Library/CoreServices/Finder.app</url>
</vkopenurldef>
<item>
<name>Eject to Open Finder</name>
<identifier>Eject to Open Finder</identifier>
<autogen>__ConsumerToKey__ ConsumerKeyCode::EJECT, KeyCode::VK_OPEN_URL_FINDER</autogen>
</item>
</root>