A few weeks ago Jason D. O'Grady posted about the news that a person was able to get Mac OS X running on an OQO. Prior to that Kevin Tofel had Mac OS X running on a powerful Samsung Q1 Ultra Premium UMPC device. I have the Fujitsu U810, but use it as my primary travel computer and didn't want to mess things up so I was hesitant to give this a try on my device. However, I just read on the GottaBeMobile forums that a brave individual was able to get Mac OS X, Windows Vista, and Linux Ubuntu all running on his Fujitsu U810 UMPC device.
The Fujitsu U810 only has an Intel A110 800 MHz processor and 1GB of RAM so it seems to really be pushing the limits to run Mac OS X on this device and may not be that functional for regular usage. The people that have hacked their devices all seem to have trouble getting WiFi running with Mac OS X on these devices too so I won't be performing the update myself, even if it is cool to see. There has been quite a bit of talk and enthusiasm for a compact Apple device and I hope that someday Apple will release a device larger than an iPhone and smaller than a MacBook.