Smarthome has a public beta of new Insteon SwtichLinc like dimmer that does not need a neutral. Some houses do not have neutrals in every switch location which means they cannot use current SwitchLincs

How it Works
The INSTEON 2-wire Dimmer Kit comes with two main pieces: a companion switch that installs in the switch box and a fixture dimmer that installs in your light fixture. With these two devices you'll now be able to convert one of your two wires in your switch box to a neutral, enabling reliable control of your light. The companion switch and fixture dimmer are "paired" at the factory so both devices will act as one. This means that once they're installed, you won't have to go back into the fixture, either for control OR for linking to other INSTEON-compatible devices. Simply put, the companion switch's SET button acts as a remote SET button for the fixture dimmer, giving you added convenience and flexibility.

Sounds a lot like the switches that are wired up to ceiling fans to allow separate fan and light controls from a single switch

Check out the discussion on the Smarthome forums