Thanks for the positive feedback!
My goal was three different islands of completely different shape, and that seems to have worked well. It's all on basic PVC stands. Here is a sample from the first time I aquascaped this tank with two islands...
I ended up using basic box shapes on both the right and left islands, and made an angled "table" for the center island, angling down from the back. What you can't see on the center island is the runway through the sides -- the hole in the front is just as large on both sides and it makes for great fish swimming lanes. You can see the PVC still on the far left wall and under the zoanthid colony centered on the middle island.
What I like best about doing it this way is that you dont have a pile of rock destroying flow -- while still being able to aquascape against the back wall. My sump returns point directly down behind the right and left islands, and the tank is bare bottom in the back corners -- for me that's perfect, that's the one place I can't get a siphon tube into, and with the returns pointed there everything gets pushed forward through the passageways in the islands where I can get at it with a siphon tube or my Tunzes can swirl it up and over the overflow.
The only drawback I can see from this is potentially visual (it takes a LONG time to get rock stacked to where not much PVC shows and in a shape you like), and in terms of filtration -- you need to go heavier on the skimmer and refugium since there's not as much live rock. This is a 125 gallon tank with sump for about 140 total gallons of water volume, and I only have 90 pounds of LR.
My fish do lots of swimming, they have lots of room.