If you build Mono from svn r100264 or newer and use mojoPortal trunk it can work and the CSS Adapaters are working. Kudos to Dean! It looks great!
The only problem at the moment is I don't have my latest updates merged into trunk because the Novell Forge svn server is acting up.
However, if you get mojoPortal trunk and using MonoDevelop, remove the compiler directive EXCLUDEVPP it should work.
It "may" also work compiling from Windows with vs, but in this case add the compiler directive MONO to the web project.
The 184.108.40.206b version of mojoPortal is needed to work with current release versions of Mono but current release versions do not have support for CSS Adapters.
Hope it helps,