I will write a status report tomorrow (propably), but here’s little something for the brave.
my NetworkManager branch:
svn co http://svn.gnome.org/svn/NetworkManager/branches/mbca NetworkManager
my network-manager-applet branch:
svn co http://svn.gnome.org/svn/network-manager-applet/branches/mbca network-manager-applet
network-manager-applet must be configured using –with-mbca switch to enable Mobile Broadband Configuration Assistant.