openings for white which don't involve a central pawn push It appears that black has more choices with regard to openings rather than white. While white would typically start with either e4 or d4, or sometimes c4, black has numerous choices for each of these openings. So a black player has a greater chance to out-prepare his opponent. I would like to know about openings white can play which don't involve a central pawn push, but which are nevertheless solid. This can take the black player out of his preparation. I do play the KIA (King's Indian Attack) sometimes. I don't really like the Reti so much though. Any other suggestions?
Since, you're already familiar with the King's Indian Attack and are looking for a solid line, I recommend playing the Nimzowitsch Larsen Attack, by first playing 1. Nf3. 

Normally, the Larsen Attack starts directly with 1. b3, but after 1...e5, I wouldn't describe the resulting positions as "solid" for White, but rather more "dynamic". 

  [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

  1. b3 e5 2. Bb2 Nc6 3. e3 Nf6 4. Nf3 (4. Bb5 Bd6 5. Na3 $5 Na5 $5) 
 (4. c4 d5 5. cxd5 Nxd5) (4. d4 exd4 5. exd4 d5) 4... e4 5. Nd4 Nxd4 6. Bxd4 Be7 *


1. Nf3 avoids the 1...e5 line, while at the same time maintaining the flexibility of transposing either into the King's Indian Attack or the Nimzowitsch Larsen Attack. 

You can get positions similar to the Colle System (very solid and easy opening for White to play, without needing much preparation). Here, I give some sample lines where you can play the Nimzowitsch Larsen attack (often transposing to Colle), or, if you don't prefer certain types of positions, transposing back to King's Indian Attack (although rare). 

     [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]


     1. Nf3 Nf6 (1... g6 2. e4 c5 3. d3 Nc6 4. g3 Bg7 5. Bg2 e6 6. O-O) (1... c5 2.
     b3 d5 3. e3 Nc6 4. Bb2 Bg4 (4... a6 5. d4 Nf6 6. Bd3) 5. Be2 (5. h3 Bxf3 6.
     Qxf3 a6 7. d4 e6 8. Nd2 Nf6 9. Bd3 cxd4 (9... Nb4 10. dxc5 Bxc5 11. O-O) 10.
     exd4 Nb4 11. O-O Nxd3 12. Qxd3) 5... Nf6 6. O-O e6 7. c4 (7. d4 cxd4 8. exd4
     Bd6 9. Nbd2 O-O 10. c4) (7. Ne5 Bxe2 8. Qxe2 Nxe5 9. Bxe5 Be7 10. c4 O-O 11. d3
     ) 7... Be7 (7... d4 8. Nxd4) 8. cxd5 Qxd5 9. Nc3 Qd7 10. Na4 b6 (10... O-O 11.
     Bxf6) 11. d4 cxd4 12. Nxd4 Bxe2 13. Qxe2) (1... d6 2. d4 Bg4 3. Nbd2 Nd7 4. h3
     Bh5 5. b3 Ngf6 6. Bb2) (1... d5 2. b3 Nf6 (2... Bg4 3. Bb2 (3. Ne5 $5 Bh5 4. d4
     Nd7 5. Nd3 e6 6. Nf4 Bg4 7. h3 Bf5 8. e3 Ngf6 9. Bd3 Bxd3 10. Nxd3 Bd6) 3...
     Bxf3 4. exf3 e6 5. g3 Nf6 6. f4 Be7 7. Bg2) 3. Bb2 Bg4 4. e3) 2. b3 d5 (2... d6
     3. d4 g6 4. Bb2 Bg7 5. e3 O-O 6. c4) (2... g6 3. Bb2 Bg7 4. e3 (4. g3 $5) 4...
     d5 5. d4 O-O 6. Nbd2 Bf5 7. Bd3) 3. Bb2 e6 (3... Bg4 4. e3 e6 5. h3 Bh5 6. c4
     c6 7. Be2 Nbd7 8. O-O Bd6 9. d4) 4. e3 c5 5. d4 Nc6 6. Bd3


EDIT: 

This is a funny yet practical suggestion. If you really want to take the Black players out of their preparation, then why not try Anderssen's opening? (lol) 

     [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

     1.a3!? 


Indeed the great Anderssen himself, in his match with Morphy (the greatest player of that era), tried this opening and scored one win, one loss and one draw, which is not a bad result at all against a player of Morphy's caliber. 

Objectively speaking, the opening doesn't offer White any advantage, but it doesn't make White's position worse either. White essentially plays as Black, as though Black had played an extra move 1...a6. As you know, the move 1...a6 is quite useful in openings like the Ruy Lopez, Najdorf Sicilian, Benoni, Benko Gambit, Slav, etc. White's aim therefore is to play as Black and try to get into these type of positions to make sense of the move 1.a3. Practically, this move is worth a try if you want to disrupt Black's preparation or like playing certain positions as Black where 1...a6 is useful. 

I give some sample lines where White tries to get into the desired positions mentioned above. 

      [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

      1. a3 d5 (1... c5 2. c3 (2. b4 $5 cxb4 3. e4) 2... d5 3. d4 e6 (3... Nc6 4.
      dxc5 $1) 4. Nf3) (1... Nf6 2. Nf3 d5 3. e3 g6 4. c4) (1... e5 2. c4 Nf6 3. d3
      Nc6 4. Nf3 d5 5. cxd5 Nxd5 6. e4) 2. Nf3 Nf6 3. e3 c5 4. c4 d4 5. b4 *