The other thread got going fast, but I think a better discussion might come out of this question:
For a "new" amiga-like OS, what parts are important for you?
What sort of hardware should it support?
What sort of hardware can you go without?
What features should be present?
What are "must have's" from the old amiga os?
In short, what is your wishlist?
Supports ARM processor derivatives.
Has 16bit sound, fast 32bit graphics, has hardware 2D/3D acceleration, dual display support, TV out.
Built in Wi-Fi, usb 2 or 3, SATA. Comes in a desktop wedge

New features: memory protection, Virtual memory (but only when required), Multi thread/core support.
Same Amiga filesystem layout (it's so easy to understand!), Fast multitasking, Amiga themed, Draggable screens, launches old software transparently.
Your doing some interesting threads these days Runequester.