Hi Privas,
It will certainly give a very sophisticated feel if one can fade up the light in a room.
I propose a solution that could be constructed for about 3$.
Below is the circuit diagram. The only limitation is you need to use a transformer. The triac is trigerred based on zero voltage crossing.
A PWM waveform could be easily obtained from a SG3525 IC whose reference is driven by a high RC time constant capacitor. Once powered on, the capacitor voltage rises, the PWM increases. One could use a period of 600ms to 1s. (I have not put up this part - if needed I'll post later)
So, the number of cycles passing through the lamp keeps increasing as PWM increases. Finally it's always on - so full brightness.
Comments welcome on this solution.
I can post a better solution without the transformer if I get time later.
Giri