Do you believe they own the copyright, or do they just have a license?
Okay, I'll try to sum it up for you (believe it or not, the following summary is the
simplified version):
There is only one entity that claims to own the Kickstart ROMs (amongst other things): Amiga Inc., available (sometimes) at
amiga.com. There are several problems though:
1. They licensed most of the rights regarding the Kickstarts, including the right to distribute them in anything but simple emulator-autostarting-a-single-game packages or Amiga-in-a-joystick type hardware, to another entity
exclusively:
Hyperion Entertainment. Both parties hate each other with a vengeance, and neither trusts the agreement between them (which is available
here) or intends to abide by the rules defined in it. You could ask Hyperion for a license, but they're probably just waiting for some idiot who's testing if Amiga Inc. can still pay its lawyers.
2. In an effort to avoid paying taxes, landlords and former employees or partners, Amiga Inc. moved, restructered and renamed itself half a dozen times in the last decade. At the end, nobody cared enough to bring them down, but you won't find many people who wouldn't agree that some really shady stuff has been going on. Even if they did own the IP in question at one point in time, it would probably be easy to finish them off for good. And that's not even counting the paperwork for all these IP transfers and sales, which is a horrible mess (we know, because it was documented in a court case).
3. Nobody knows, if Amiga Inc. ever owned the Kickstart ROMs. They allegedly bought them from Gateway, who allegedly bought them from the bancrupt ESCOM in 1997, who had allegedly acquired them when buying the bancrupt Commodore in 1995. But in 1997, a German judge ruled that ESCOM didn't provide any paperwork that proved they acquired the Kickstart rights along with the trademarks etc. That doesn't mean they didn't have such paperwork lying around somewhere (the company was long defunct when the judge made his decision), but it was only halfheartedly fixed during the sale to Gateway a few months later.
Basically, you will probably have to contact Hyperion, or maybe Amiga Inc. (depending on the exact use for the ROMs you have in mind, see the agreement). If you contact the latter, don't expect an answer unless you promise to provide tons of money or to hurt Hyperion real bad. If you contact the former, expect paranoia and greed, and make sure you don't mind being used as a guinea pig.
Your best bet might be the effort to create free ROMs using the open source AmigaOS clone AROS. Not there yet, but they're getting closer.