Oh boy, this thread is so overloaded with spin, hearsay, and spit and venom, that it's pretty hard to pull the facts from fiction.
Here's my understanding of what the A1 is:
Designed to run Amiga OS4, the A1 boards were produced by Eyetech to be the next generation Amiga. It uses PowerPC CPUs mounted on a card; both G3 and G4 cards exist (apparently there are a few prototype dual-processor CPU cards in existence, but I've never seen them). They use SDRAM (133 MHz), have a 2x AGP slot and several PCI slots.
They are pretty much the Teron reference design created by MAI Logic. Eyetech claim to have worked on them and made improvements, but any changes probably made their way back to the Teron dev. boards too.
Unfortunately MAI logic's northbridge chipset is buggy, and they are now out of business. This results in a series of flaws for which software workarounds are in place, wherever possible. Added to this, the southbridge is a VIA686b, which is known to be buggy, even on x86 boards (VIA refusing to help out with undocumented features, etc., didn't help).
I have an A1, and for "the worst consumer product of all time" and "total garbage," it actually works quite well. The bugs have a performance hit (e.g., memory access is slower than it should be), but Amiga OS4 works well on it and is fun to use.
They are no longer produced, for obvious reasons: the chipsets are buggy and the specifications are dated. Unfortunately, no replacement system has been forthcoming. Sure there are plenty of PowerPC hardware that could theoretically be used to run OS4, but no licenses have been given, and legal issues are blocking this.
Hans