I was reading through the old Giant Stair's scenario from Stormbringer thinking it was more or less a Hero Quest. The gateway only opens at a certain time in a specific place, the PC's are on the other side, time passes differently, etc. It works for me.
Thinking of potential powers a giant might have that would be interesting, titan stomp which makes one fall to the ground, billowing voice which makes one cower in fear... of course the giant would have a smell food skill or something of the like.
What else beside throw rock 100's of meters might a giant have?
Are there Hero Quests with giants in them?
Are there other scenarios beside Snake Pipe Hollow, Balastor's Barracks, Orta's Castle and Willandring the Giant that have giants in them that are not random wilderness encounters?