Starwood Preferred Guest (SPG) has two status levels Gold and a Platinum. They do, however, has Preferred Guest Plus (Gold lite) that comes with guaranteed 4PM check out and a space available room upgrade.
You can get Starwood Preferred Plus for simply being a AAA member, but now there is a direct sign up offer available as well.
You can access this offer on Starwood’s web site here.
Edit: Starwood has extended this offer to number of businesses but there are no Terms and conditions to attached to this offer.
Note that there is Starwood Preferred Guest Gold offer available in Asia Pacific region that requires just one stay. You can read more about it here.
I signed up a family member using the link and the upgrade was instantaneous. You should be able to upgrade your existing account using this offer as well.
This is a great way to get that confirmed 4PM check out without having to pay a penny more (applies to non-resort/conference locations) and a room upgrade.