Hmmmm. Let's not forget that the Air Force charter specifically requires them to provide air support for the Army on the ground. When the USAF was created in 1947, they had to maintain that focus. In the 1970's, the Army challenged the Air Force and they had a large exercise over several weeks just to show that the Air Force could move so many millions of tons within a short time. They almost couldn't do it and nearly lost their charter!
In my opinion, the A-10 is the only direct support aircraft around. Remember when they were thinking about pulling it from the inventory before the first Gulf War?... then it proved itself remendously. In fact, pilots would come back and ask just for bullets... no time for missles (and the bullets chewed up the tanks pretty darn good).
What else do we have? F15E Strike Eagles?
Uh... 1000 pounders are not exactly close proximity weapons.
Attack helicopters provide excellent close air support.