The below document has the only known screenshots of Guerrilla currently in existence. The "Confidential" part, of course, no longer applies since this was from back when they were pitching the game and the IP is not held by any company.
After Ghost, there was also a small period of exploration starting Ghost over in a new direction, or the Blizzard Console team designing other games using Blizzard IPs. During the ramp up to complete SC Ghost, SAS went from a small 12-16 strong company to over 60 people (including artists, programmers, and testers.)
Later, Steve left Blizzard and formed Specular Interactive and returned to his roots, I'd guess you say, working on the arcade title "H2Overdrive" (much like his original "Hydro Thunder" arcade game.) Their most recent arcade title is DIRTY DRIVIN'.