@NotFastEnuf: My understanding is that for a 2" build, you just have to watch your weight. This is a bit harder with heavier 1104/1105 motors, as opposed to the lighter 1102 or 1103 motors. However, with the bigger motors, you can use a 500mAh LiPo, whereas for 1103, the sweet spot is closer to 300mAh. Given the excess power of brushless micro motors, 1104 6500KV and 2" quad-blade props should fly just fine on 2S, and rather fast on 3S.
For good 2" examples, look up the AirBlade Creampuff, RotoRex Nyuki 100, or FlexRC Pico X on RCGroups.
Disclaimer: I haven't built or flown a 2" brushless myself. I'm a so-so pilot, and sticking to 3" and 2.5" for now.