Seems that applying all of the patches discussed previously has broken my version of Solaris, as it now seems to have problems booting.
It seems to hang during the boot cycle, so I had to do some hunting to try and find out the cause.
Boooting with a -v (verbose) shows that the system is hanging in iscsi.
After some googling it seems the only way to fix this, so you can get in is to do the following..
1. Boot using -m milestone=none
2. Login as root
3. svcadm enable -r filesystem/minimal
4. svcadm enable -r filesystem/local
5. cd /etc/iscsi
6. mv iscsi_v1.dbc iscsi_v1.dbc.bad
Now you can get in, I suggest you go and install the latest iscsi path from sunsolve:
Patch number 119091 for x86 Solaris.
reboot and hopefully all will be well.