Can 'Find My Mac' work while the computer is sleeping? Is the 'Find My Mac' feature of iCloud supposed to work while the computer is sleeping? I use this feature to check on things every once in a while, as well as show the feature off to other people. Every time I show them though, it always lists the machine as being offline. 

I ask too because a 'sleeping' mac does actually wake up every once in a while (in a very low level state), to basically check and update its mDNS/Bonjour config, as well as a few other minor things (I know specifically my iMac does this, I haven't looked on my MBA). I figured that if it was waking to at least check this stuff, it would also propagate to Find My Mac.

Final Update: So after switching around more network configs (and going just wifi), it actually worked worse - I couldn't wake the machine locally either (and this is with wake on network access checked). So I think its either something odd with my setup, or actual machine (I know already wifi is odd on it - I tried a defaults command to enable airdrop, and that didn't work either). My actual issue is due to the machine not being able to wake from sleep.

New Update: So, noticed a few things. Wifi was on, but not connected (nor should it be). I turned it off, and disabled the interface, and it still doesn't wake the computer up on the Ethernet adapter. I just now tested the opposite way, and it actually looked like it worked! Want to try again a bit later to make sure.

Update: I re-enabled Find My Mac, and verified that wake on LAN was active. While it did work earlier on, once the computer actually went to sleep (about an hour later), it never seemed to want to update, until I woke the machine. Is Find My Mac supposed to wake it anyways? Or would Find My Mac while sleeping never actually show its current location until the next wake? As a precaution, I restarted my Mac and Airport Extreme just recently. Also, could this be a port forwarding issue on my FiOS router?
If the Mac is sleeping there is no way for iCloud to locate it and it appears offline. 

However, as you noted, you can enable Wake for network access in energy preferences for it to periodically wake and check the network allow remote wake up using and AirPort.

When the Mac connects to iCloud next time, your commands (locate, lock, wipe, message/alert) are sent to it.