The current IETF draft (still a work in progress disclaimer), is called Sleep Proxy Service, an extension of mDNS (aka Bonjour). Source code is here, but as far as I know, no other router has grabbed any of it. Might be able to get it to work against one of the open source firmware projects like OpenWRT. Looks like they have a feature request for it already, but no work has been done.

As for Wake on Demand and WiFi, there wasn't a good clear cutoff on what models support it and what don't, as Apple has sometimes swapped out WiFi boards midmodel. The best way to check is referenced in the KB article I linked earlier. Basically check System Profile under Airport for "Wake On Wireless: Supported" Also, there is notes in the article regarding how to get Wake on Demand to work if the laptop lid is closed. Kinda a PITA currently, as it involves waking the system once after closing the lid.