IBM ThinkPad T20/T21 with fresh laptop install of 7.1 RC2 qa0401. With the power unplugged pressing fn+f4 puts the system into sleep state (Screen blanks, system beeps various times, wireless nic shuts off, sleep LED comes on.) Leave it alone for a while (5min to an hour or even more) and try to wake the system by pressing fn or any other key. system refuses to wake. At this point you need to hold the power button down for more than 5secons to force a reboot. Because the NIC goes to sleep and doesn't wake with the system I cannot telnet/ssh in to verify the system is really alive.
This is a BIOS problem. Neither Linux nor any other OS can do anything while the machine is in sleep mode. (Doing just the same thing works perfectly on other hardware; I'm using a Gericom 3xC and a Fujitsu LifeBook C, I've also tried to reproduce this on various other machines without success.)