Since the OpenSolaris install disc is a LiveCD it's easy enough to non-destructively test on any hardware you can get your hands on. If you know someone with a laptop you're considering or if you buy things retail, just pop in the CD and reboot. Everything worked out of the box on my Lenovo Thinkpad X300 btw.
Its not a list maintained by the vendor, but there is a community driven hardware compatibility list maintained on Sun's website. You can find it at:
http://www.oracle.com/webfolder/technetwork/hcl/index.html
Since the OpenSolaris install disc is a LiveCD it's easy enough to non-destructively test on any hardware you can get your hands on. If you know someone with a laptop you're considering or if you buy things retail, just pop in the CD and reboot. Everything worked out of the box on my Lenovo Thinkpad X300 btw.