There are of course ROM switchers for the kickstart. But there is also the ROMulator, which happens to be out of stock at the moment:
http://amigaonthelake.com/romulator-...miga-500-2000/
This allows you to select a kickstart at bootup.
There is also this, DIY project:
https://github.com/SukkoPera/OpenKickstartSwitcher
I realize it is not quite what you are asking about but both of these solutions work well. Well, I know the ROMulator works because I have one. I have boards for the kickstart switcher project but havent built one yet.