Today i  tried the opensolaris developer release (project Indiana). It looks very promising, i especially liked the used nimbus theme. I wanted to install this theme in my gutsy, but could not find amd64 packages for it. So i build these packages using the guidelines from Make your ubuntu more beautiful. If you need the packages you can find them here  :

• gtk2-engines-nimbus_0.0.6-1_amd64.deb (46K)
• nimbus-icon-theme_0.0.6-1_all.deb (8.5M)

I hope they work for you