I am just getting into hacking the i-opener, but I know a thing or two about OS/2. I haven't tried OS/2 on an i-opener and would hesitate to do so for the following reasons.
1. Drivers. Unless you are proficient in coding drivers and know OS/2 very well, you'll be hosed on the drivers for just about every aspect of this motherboard. The video certainly won't work above 640x480x16, that much I can guarantee.
2. USB. Currently, no version of OS/2 has USB support. Although there are some folks working on open source solutions to this, nothing currently works.
3. Hard drive. Be cautious. OS/2 Warp 4 still have sever cylinder limitation on the hard drives you could use with it. You'd be best to get a hard drive from an old laptop.
I could probably go on with some more reasons, but if you've read this far and are still interested in putting OS/2 on an I-opener then go for it. You can reach me anytime for questions about OS/2.
If you really want to learn OS/2, I'd recommend buying a copy of OS/2 Warp 4 on ebay and getting something in the neighborhood of a Pentium 200 with 4.3gb HD. You can max out the RAM as much as you like, it can only help. A machine of this stature will run OS/2 very well. I recommend an ATI Rage IIC 3D card for video, it performs very well in OS/2 and is very stable.
My OS/2 workstation is an old AT&T Pentium 133mhz with 64m RAM and a 2.1gb HD and it runs pretty well, surfs the web OK with Opera for OS/2.
Hope this helps...