In my case I've got a separate Mac mini server thats on 24/7 (consumes 41 watts even with 8TB of drives) so sleeping the other systems, with wake on LAN off, is not an issue. In fact, wake on LAN is a problem because of the proxy action of the Airport Extreme causes the waking system to see another of the same name and then rename itself. It's been a bug ever since that feature was added to OS X.
Yes, I thought of getting a Mini for homesharing. Probably the ultimate solution