@Todd
I wouldn't worry too much about the drivers only in the OS problem per se. From what I understand, the kernal/ROM/kickstart will be on HD/disk and not in the BIOS rom. But don't dispair over this fact. To a certain extent, that is true even now. Let me explain.
Unless you have a bootable floppy or a bootable HD on a current amiga, you can't get to a CLI prompt or really do anything. This is because there is Boot code on the floppy which enables the different sections of the kickstart ROM itself. This can also be custom boot code like one might see on a demo floppy or a game floppy. This also true with RDB boot blocks. The actual filing system code is effectively embedded in the RDB. That is why a PFS drive can be pulled from one amiga to another without the second amiga having ever heard of PFS.
So what does this mean? Well, more than likely, they will embed the entire kickstart rom on a boot sector/RDB level. Or at least to get it up and running enough to go to something more complex. You are doing this right now, so I wouldn't worry about it. It just will be more code. About the only thing you will have extra is a PCish text boot screen until it hits the HDs and loads the ROM. And technically, in later revisions, there shouldn't be a problem (not that I have anything to do with hyperion) to have a splash screen covering up the text boot process. I say that because I have seen that done commonly on Dell, Gateway, and many other name brand machine's BIOS. If that is done, you wouldn't even know the difference between the new A1 bios boot up and the older "classic" amigas at that point booting up.
Does that help any?