I was actually just now on the phone with Oracle about an unrelated matter, and they've confirmed with me that it's now not possible to download any patches for Solaris outside of the Oracle support system (http://support.oracle.com/).
Sorry to be the bearer of bad news.
In qemu/kvm, you only get a GUI if you attach a video card to your VM and if you don't expose it as SPICE/VNC.
For instance, you can do (zsh syntax, with grub2):
grub-mkimage -O i386-pc -c =(print -l serial 'terminal_input serial' \
'terminal_output serial'
) -o grub.img configfile biosdisk part_msdos part_gpt ext2 \
linux test serial halt minicmd cat
And start your VM with:
kvm -kernel grub.img -hda yourdisk.img -nographic
From the grub prompt, load the kernel from the disk passing console=ttyS0... option or equivalent on the system you're booting to have the console on serial. Remember to add a getty on the serial line as well.
Assuming you're running Linux in the VM, you can then update its grub config to display on serial and boot a kernel with serial console, and then you can boot your image disk directly without that grub.img.
To access the qemu "monitor", type Ctrl-Ac (where you can add/remove devices...).
You can have the serial port as a unix domain or TCP socket, instead of stdio if you like as well. Same for the qemu "monitor" interface.
Now, provided you have the sgabios.bin firmware, and that your VM doesn't use graphics (just VGA BIOS text output), you can also just use the -curses option:
kvm -hda yourdisk -curses
The VGA console is then shown in your terminal. If you need to access the qemu monitor, press Alt-2.
Best Answer
For running Solaris in dom0, no. Oracle has euthanized it. xVM worked on Solaris 10 but it broke during the development cycle of OpenSolaris (it's completely broken and unusable on snv_134, but probably earlier). Neither Oracle nor the Illumos community has shown any interest in getting a Solaris kernel running in dom0.
Oracle's replacement product is OracleVM. On Sparc that means Solaris LDOMs. On x86 that means Xen with Oracle Linux in dom0.
In the Illumos community, Joyent has ported Linux's KVM to the Illumos kernel. It's available at least from SmartOS, but I believe it's also available in OpenIndiana and OmniOS**.
If you want Xen I suggest Debian. If you want ZFS* I suggest OmniOS or SmartOS and use KVM.
* FreeBSD still can't run dom0.
** As years have passed, KVM is available in most, if not all illumos distributions and Joyent has resurrected LX-brand zones as part of SmartOS and are now also in OmniOS.