Nice try, Mark:-)

I've been busy lately, so had no chance to follow-up with your ideas.

But I was wondering.. .. do you by any chance have V5I?
If so, my wondering (wandering?) thought was:
Create terrain. Create bitmap to control eco-system (along the paths that the lava should flow down). Populate bit-mapped controlled ecosystem with lots of spheres (I think you can do that - I'd have to experiment). (Somehow) select all the spheres & group them into a metablob...

Apply texture... I wonder if it would work...

I have a "free" day tomorrow. If I get the chance, I might try that out...

Cheers,
Diolma