I've just had the 4.0.4 update. I've got the IMM76I build. This is a further build to 4.0.4 IMM76D with a few tweaks to the signal loss that people have reported.
http://www.engadget.com/2012/04/21/google-pushes-imm76i-ics-build-to-hspa-galaxy-nexus-reportedly/
http://www.engadget.com/2012/04/21/google-pushes-imm76i-ics-build-to-hspa-galaxy-nexus-reportedly/