Look, there aren't any building sites left in the immediate vicinity of the 80 Bridge approaches on the South. South Beach (which is what that area is) is pretty much all built out now. Moving south from there, you have Mission Bay but the height limits there (thank you, John Burton and the Potero Hill residents) prohibit highrises. So, SOUTH of I-80 there's really no place they are going to do any highrise development until you get to the Third St corridor and there too I suspect you will get rampant NIMBYism from Potrero Hill (though I think it might be a good place to put some highrise housing and pressure to build housing may eventually overcome the folks on the hill worried about their views).
One place a small amount of development will occur is on another part of Rincon Hill (if you will). Think of the terrain--the high point of Folsom St. is where it crosses 2nd and near there (actually just over the crest) is going to be:
The Planning Dept. doesn't consider this to be part of the Rincon hill plan I don't think, but in reality it is part of Rincon Hill terrain-wise.
Here's another rendering of it:
The design for 631 Folsom Street incorporates goals established in the Rincon Place, the Transbay Plan, and the General Plan for downtown San Francisco by creating a high-density project that preserves sunlight and air, provides open space, and enhances the development of the area.
The project consists of a 21-story residential tower over a single-story podium containing retail space and a residential lobby along. The storefront facade is setback to align with the existing street-wall. Further enhancing the pedestrian street life will be the new open space park between 633 and 631 Folsom.
The massing is tall and slender to maintain view corridors, provide sunlight and air at street level, and give units natural light. The light-colored pre-cast concrete, the bluish glass, and metal curtain wall give the facades an expression of lightness and transparency.