I'm planning on building some dimmable lighting controller for Christmas lights, but with LEDs being all the rage nowadays, I was thinking that instead of using triacs and dimming at 60/120 Hz, rectify the AC to DC and use MOSFETs to reduce the strobing that is more evident in LEDs. This might allow the controller to be smaller and/or cheaper.
This would depend on how the LED strings are actually wired up. I don't currently have any to look at, and I could imagine a few different ways they might be connected, such as diodes that only conduct for half the cycle, which would axe the DC idea if true.