So the Solaris display driver is capable of driving an external VGA display but not the laptop's own display. Have you checked whether there are any display settings in the BIOS that can be tweaked?
Can you wind the resolution down to the minimum just to see if that works?
Does this problem occur irrespective of which GUI you select; X-Windows, Gnome, or whatever?
---------- Post updated at 12:17 PM ---------- Previous update was at 11:21 AM ----------
The Intel HD 4000 is a graphics card that the OpenSXCE project (derived from Open source Solaris) has had to write a new/modified driver for so that's interesting:
View Source
Whether this driver will work on your laptop I don't know but may be worth a try since you have nothing to lose.
The authors (shown in the right column of the web page) are usually easy to contact if you search for them. I've done it before quite easily.