Looking for a aggressive positional opening

I am looking for openings with either white or black that are aggressive in that they lead to an attack, but that involve a slow positional buildup to the attack. Any suggestions. In other words I am looking for attacking lines, but not sharp attacking lines. One example of the kind of thing I am thinking of is the Closed Sicilian with white. These can start with e4, d4, c4, Nf3, I don't care. For black, maybe something like a Stonewall Dutch is like this. Any other suggestions?

Thank you Planar. Maybe I could try one of the older variations with an early d3 and play it a la Steinitz. 

KIA is a good suggestion, but KID can be very sharp and involves lots of theory (maybe there are some good sidelines?). Thanks D. Anyone have ideas about black vs. 1 e4. Here I don't mind if the opening has a few sharper lines.

In general, positions where you can slowly build up a positional attack require you to have a positional advantage, and it's harder to get that as black without giving up something major in return (material, positional weaknesses, etc).  The Benko Gambit comes to mind as black against 1. d4 for an aggressive but positional option that isn't too sharp or theory-heavy, and most Sicilians lead to aggressive play, although it might be sharper and more theoretical than you want.

With Black against 1 e4 the French offers a slow positional build up in several lines.  It's good that you don't mind a few sharper lines since it does have a few sharper lines, especially the Winawer.

Pirc or Alekhine may be other options.