Did a quick test for a bulb, doesn't itself cast light, but the effect seems *ok*
The model itself is a mutilated box, bottom face missing, with a shell modifier on it to give it thickness.
Bulb glass material is:
Standard, blinn shading
Diffuse: Pure white
Opacity: Falloff perpindicular/parallel starting at ~.05 with a sharp curve up to 1 the right - meaning, the sides are not transparent.
Reflection: Raytrace, with a mapping the same as opacity
self illumination (when on) - Glow(lume) shader with very high yellow intensity
Specular set to 0
The thing inside is:
Standard, self illumination with Glow(lume) shader with very high intensity. Black in the diffuse channel.
Specular set to 0
i then put an omni light with inverse falloff, set the outer bound to fit the scene nicely, and turned the intensity up a bit. Then I excluded the bulb stuff from recieving light from the omni. (Off pic has a sun on) To turn it off, i just turn off the omni and switched off the self illumination channels.
Used Mental ray to render (pardon the low AA), auto levels + specular bloomed a bit in photoshop. raytrace depth was 6 for everything.
