z28pwr -- I'd really like to see a pic. Thanks for the offer to look.
Ed -- thanks for reminding me of that technique. I'd seen it discussed on WetWebMedia but had forgotten it. (I think the phrase I remember was "rock popsicles".)
Louis -- those pix of the 'spindle' technique are like nothing I've read about, but it might actually be just exactly what I need, since I'm thinking of a coral-head type of look. I glanced over the article; will peruse it tomorrow. Looks like great info if I'm going to need to drill (like for a spindle). "Guess what, honey? I need more power tools..." Heh heh.
Still, the rock popsicles seems easier since I'd not need to drill big holes, just use a masonry bit I already have. Seems like it'd be easy to add to, also. But the spindle technique might allow a steadier, taller structure. I'll look into both. Or even combine them for maximum effectiveness for what I'm trying to accomplish.
I suppose the pvc framework would be best applied to when you want a big wall of rock. (Which is not what I'm trying to create.) Maybe that is why I was having trouble imagining making a "coral head" from it. You fellas sure did loosen my brain from where it was stuck! Thanks so much! ..Karl