The latest version of gnome-do, 0.5.0.1, requires gnome-keyring-sharp. Currently this is only available from bzr, or as a snapshot.
There is a tarball available here now: http://ftp.novell.com/pub/mono/sources/gnome-keyring-sharp/gnome-keyring-sharp-1.0.0.tar.bz2
Created attachment 163208 [details] gnome-keyring-sharp/gnome-keyring-sharp-1.0.0.ebuild
This is in tree now.