I see that the warehouse opens at 10am, however I'm wondering do they open earlier for members with premium/business membership like Sam's Club? Thinking about switching to Costco but I like being able to shop @ 7am...

Nope

You are right about Sams and I have used that perk many times for my business. I keep both memberships and Costco has had lower prices on many comparable items than Sams. Not sure about the early hours though.

Actually Costco doesn't do this. I shop there and unfortunately they don't have that with their executive accounts so if that's a benefit you want I would stay where you are.