Thank you all for our replies!
You see, I'm a telecommunications engineer with a strong emphasis on programming and control systems; I own 3 Macs (MacOS X Tiger), 2 PCs (Win and Linux), 1 Amiga4000 Towerized + WarpEngine '040 33Mhz (Amiga Workbench), 2 Amiga CD32s, 1 Nintendo Gamecube.
I understand what you say about this AmigaONE platform not being suited to develop for seriously, but it's AmigaOS 4 that I would like to develop for.
And it's not "serious". I don't want to make any money on this. I develop on the Mac, PC and Linux for that. I want to develop on the Amiga to try to strengthen a bit the platform, to contribute, for fun. Just like the Amiga was in those glorious days... I just loved the simplicity of Workbench.
Thing is my Amiga4000 is stopped at the moment, and although I will try to make it run again on it's old self (Workbench 3.1, I guess), I want to develop for the new OS, no matter what hardware they will run it on in the future.
So, I would like to get hold of a developer board and install the Hyperion AmigaOS 4 developer kit. But as some people mentioned, it seems to have vanished from sight... I can't seem to find it anywhere, not even on eBay second hand.
I confess I've lost track of the Amiga headings lately (I mean, in the last 3 years), but I think they need to define a hardware base so that AmigaOS 4 can be a viable platform. And although it might never cause Jobs, Bill or the Linux community any kind of chills at night, I'm sure it would find a niche market. The Amiga had this spirit that kept us smart and active. The Mac is the next best thing on a much greater scale, but I'm not ready to give up on the Amiga if I can contribute to make that spirit endure.
I spent lots of years as an Amiga user (A500 - A4000T). I loved each hour and I learned a lot from the computer and community. I'll keep trying to get the developer system from somewhere and update myself on the Amiga situation.