I've recently developed some TriX in Acutol 1:9 that gave me some really nice crisp and VERY sharp grain. I was using a noctilux wide open and rated the TriX at 400 for some interior nighttime shots. I developed for 10 minutes at 70 degrees, and they turned out wonderfully. Since you shot at 1600, you could probably increase the time to 15 minutes or so and get acceptable results. The thing that I liked about Acutol over Rodinal was that it did not seem to increase the base fog as much as Rodinal tends to do when you use it at 1:25. The grain was very similar, however. If grain is what you want, then definitely stay away from solvent developers like ID-11, which contain sodium sulfite and will tend to reduce the grain.

That said, in a pinch you could dilute the ID-11 to 1:3 and develop for 30 minutes and get the grain you are looking for. Just be sure and put some empty reels in the tank so that you use an appropriate developer volume of at least 4 ounces of stock solution per roll of film.