Short-barreled rifles (SBRs) are covered by the National Firearms Act of 1934.  Depending on which state you live in, you may be able to have one right now, though to make one, you'd need to pay a $200 tax and submit a Form 1 to ATF along with some finger print cards and some passport-type photos.  You also need to get a sign-off from the chief LEO in your area.  None of this will change.  Note that a SBR is still subject to the AW ban, so you can't add AW features just because you made your AR into an SBR.

Pistols are also covered by the AW ban, and the rules are different than for rifles.  Essentially, there's no legal way to make a conventional AR pistol without using a lot of specialized parts, and eliminating many features, including the handguards.

Yes, when the AW ban expires, you could make a standard AR pistol if you wanted to.  Still, AR pistols (at least, those in 5.56mm) are LOUSY weapons, and are really only suitable as a range toy.

-Troy