I had mounted an SPS branch to a piece of LR one time, and got a really interetingly shaped colony... The frag was maybe an inch, 1.5 inches long? Slightly curved. I glued it so that the tip was point down, towards the rock, and glued the other end down as well. there was a very small gap between the coral and the rock.
When it first encrusted, it didn't look like it was going to be very nice. However once it started to actually take off, it was very kewl. A nice rectangular shaped colony, almost. There were raised corralites on the 'top' side of the frag, running in a linear pattern from the base to the tip. These all grew into new branches, as did the preceding and next row of corralites. This produced a very interesting shape, and worked well. It did take a long time for the coral to grow out, but this was a slow-grower anyways.
- Mac