Clouded Glass Shader?

[apotheosis]

I'm new to Maya, so I apologise if this is an incredibly easy or silly question.
But, I am trying/desiring to make a shader that will render something somewhat like a glass marble, in that there will be areas of colour and opacity, throughout the volume of the material, as well as areas of transparency as opposed to an opaque skin only on the outer layer. The effect I'm after is somwhat like mucus (ew), or blood or milk, suffusing through water, or the white cloudy parts of an ice cube or the flowers within jade - though with the main body transparent rather than transluscent.
I'm wondering how do I go about creating such a shading network? my Original thoughts were using the volumetric shader (with a base 3d fractal texture to begin with, until I get the effect down, the details do not matter), but I'm unsure of how then to connect this to another shading group the methods I've tried lead to the skin effect. All the tutorials I can find are about getting environmental or light fog, which isnt what I'm after...I fear I'm after the impossible...
My other thoughts were that I'd have to actually script the effect...which I have similarly little idea of how to acheive.
In summary, a quick how to, or indeed an indepth walktrhough would be greatly appreciated.
Thanks in advance

[joojaa]

No its not silly... Its a computatinolay outrageous operation. And hasnt been implemented in the renderer by default. There is a raymarch plugin available that can do this but im not sure if its been recompiled to the newest version. Such things a much better to be left for mental ray to handle.

The idea is to raytrace from the surface in small steps untill the ray either exits th surface if not then accumulate a buffer of some kind...

[apotheosis]

Ouch, exactly how computationally outrageous?
I am using Maya 4.5 (so hopefully latest version recompilation isn't a major issue), so if the raymarch plugin is availble for general usage without laying out the dollars, I might use it in my project for university anyway, and try and swing a renderfarm.

If the final point a hint that can be done without the plugin through some other less conveinient means?

Thanks for the clarification though

[joojaa]

Well depends on the amount of samples but ina general for good resuts, But very expensive. Depends on the quality you need.