As of last night I now have Leopard 10.5.6 running on my Acer Aspire One X150.
I blew away the XP partition to do it, though. No matter.
I used an external DVD drive with a torrent of iAtkos v5i.
Sound and camera are working; wireless is not. Sleep does not work.
The external monitor works, but I have not yet found out how to get the desktop to see it as primary, and trying to mirror it crashes the system.
Other than that, following the instructions I found on AspireOneUser.com worked for me. I caution you to follow the instructions EXPLICITLY, there are lots of little potholes to fall into.
http://www.aspireoneuser.com/forum/viewtopic.php?f=14&t=7802&sid=7534546374e4a4b6ab51580cf1e0479b&start=0.
I can probably live without the wireless. My inclination is, if I need to go out and do browsing in public, to get a wifi dongle for it.