Do you want to water cool or not? Are you saying you don't want to build a custom loop? The Kraken g10 exists but I don't think you could fit 3 of those for tri-fire. The tri-x cards should be fine for small overclocks. The 3 cards next to each other means they will all be hotter. As long as you are fine with like 85-90 degree temps you should be fine. That is still within the safe operating temperature range.
I don't think an AIO option would work for tri-fire. The lightning cards are 2.5 slots wide, and I don't know of a motherboard where you can tri-fire those so that wouldn't work, and it is well known the tri-x is the next best thing. Go for those and you won't be upset.
Or you could quad-fire 290s and still save money and get more FPS. Tri-x 290s are cheap right now on newegg I believe.